Special Publication, April 27, 2021
Israeli security officials may be uneasy when seeking to understand the threat posed by the Houthis, due to the movement’s opaque nature, its geographic position in a more distant range for Israel’s intelligence and operational capabilities, and hybrid functions, which include almost caricature-type militia qualities, advanced military capabilities, and state-like institutions. Precisely for these reasons, a nuanced understanding of the group – an increasingly assertive component of the region’s broader strategic environment – remains essential for informed and effective management of Israel’s national security priorities.
This paper examines the Houthis’ strategic approach to Israel as well as the group’s operational capabilities and practices. The authors aim to provide an assessment of the Houthi threat to Israel, and thereafter offer five key insights for Israeli decision makers. The ultimate goal of this work is to shed light on the contents of this mysterious “black box” to serve Israeli national security decision makers.
The paper’s conclusions are as follows: Despite their rhetoric, the Houthis do not appear to have taken a decision to strike Israel, and they might never decide to do so. However, strategic developments in the region, such as intensifying pressure from Iran or a shift in domestic Yemeni dynamics, could make a Houthi attack on Israel more likely. The Houthis’ willingness to strike Israel on behalf of Iran remains an open question, although at present, the Houthis do not appear to have the capabilities to pose a major strategic threat to Israel. Even without direct hostilities between Israel and the Houthis, developments in the Yemeni civil war could affect Israel negatively, as the theater serves as a testing ground of sorts for Iranian weapons systems. A Houthi strike on Israel or the group’s accumulation of a disproportionate stockpile of weaponry that threatens Israel will present the Israeli leadership with a dilemma of if/when to strike – at risk of being drawn into the Yemeni quagmire.
II. The Houthi Strategic Approach toward Israel
The Houthi movement is a social, religious, political, and military group that emerged from the Saada Governorate in North Yemen. In the 1980s and 1990s, a number of trends in Saada, including neglect by the Yemeni government, Shia fervor following the Iranian revolution, decline of traditional tribal structures, and the rise of Salafist currents, converged to create an environment conducive to Houthi (Zaydi-Shia) revivalism. The early stages of this movement included summer camps and parliamentary participation, but by 2004 it had evolved into a disorganized armed insurrection. The Yemeni government sought to crush the insurgency through heavy-handed tactics (2004-2010), which inadvertently served to strengthen the movement.
The so-called Arab Spring created further opportunities for Houthi expansion after the transitional government sputtered and then stalled, and by late 2014 the Houthis took control of Yemen’s capital, Sanaa. Since then, the group has steadily expanded its military capabilities as well as the scope of its activities. The growing range of its weapons and the group’s rising interest in regional affairs thus leads to the question: what is the Houthi approach to Israel?
B. The Houthis as a Local and Regional Actor
The Houthis are simultaneously a loosely organized domestic group focused on local, practical interests as well as a core component of a regional-oriented and ideological cadre of Iran-backed Shia militias. Information on developments in Houthi-controlled territory is generally scarce, but some evidence has emerged of growing local disputes (both within the group as well as between the group and local populations in territory conquered by the Houthis). A recent ACLED report sheds light on the intensifying internal competition among Houthi leaders:While expected to show ideological commitment to the Houthi cause, local commanders also enjoy relative autonomy, operating as a network of militias that are involved in the extraction of levies and the recruitment of fighters in support of the war effort. This “cartel-like” structure, however, is prone to stoking tensions within the movement. Rival factions are reported to exist among senior Houthi officials competing over access to positions of power and control of rents…Data recorded by ACLED reveal that infighting within Houthi ranks reached a new peak in 2020.
In contrast to a decade earlier, at which time the group’s expansion depended on familial ties and inspiration rather than intimidation, the Houthis’ domestic disputes have increased in tempo and their outcomes are more often determined through the use of violence.
In parallel, the Houthis – or at least the group’s leadership – also harbor broader regional aims. For example, in 2019, Houthi radio station Sam FM announced it had raised around $300,000 to support Lebanon’s Hezbollah in face of budgetary challenges caused by the US “maximum pressure” campaign against Hezbollah’s Iranian patron. Local interests would dictate using those funds in Yemen, where the population under Houthi control faces extreme poverty, starvation, and disease, but the group defended their decision to channel the funds to Lebanon, claiming that it was “what the Yemeni donors prefer.” This campaign may have been a genuine fundraising effort as described by the Houthis, but it is also possible that the public campaign served as a cover for various activities, including the extortion of Yemeni citizens to pay Hezbollah for services rendered or a money-laundering effort to transfer funds from Iran to Hezbollah. Regardless, the publicity of the campaign seems to highlight Houthi regional aspirations.
Also, in 2020-2021, in what is likely an effort to demonstrate their commitment to the Palestinian cause, the Houthis have sought to gain the release of Hamas prisoners from Saudi jails in exchange for the release of Saudi airmen captured by the Houthis over the course of the Saudi campaign in Yemen. Once again, the Houthis appear to be using their limited resources in a manner that prioritizes a regional rather than a local agenda.
In deference to the patron of the “resistance axis,” the Houthis signal consistently that they aspire to replicate the Islamic Republic model in Yemen by adopting language from the revolutionary regime’s lexicon and sometimes expressing outright admiration for Tehran. A February 2, 2021 tweet from a Houthi-affiliated account that appears official and claims to support the families of “martyrs” noted that “the soft war is more dangerous on our young people and women than warplanes.” “Soft war” is the very same terminology used by the Islamic Republic (jang-e narm, in Persian) “as a euphemism for the spread of foreign ideas, culture, and influences through information communication technology.” In addition, on the 42nd anniversary of Iran’s Islamic Revolution, longtime Houthi spokesman Mohammed Abdelsalam tweeted his veneration for the regime in Tehran: “We congratulate Iran on the 42nd anniversary of the victory of its Islamic revolution. It is achieving progress in all fields, and it is a unique and distinct model in the Islamic world for an independent, strong and capable state.”
Still, the relationship between the Houthis and Iran is complicated and ambiguous. There is undoubtedly an ideological affinity between the two, which allows Tehran to exert influence beyond that of a standard patron. At the same time, the Houthis have not yet indicated that their strategic aims are to serve Iran’s interests when doing so diverges from their own domestic concerns. As the bilateral ties evolved in recent years, the Tehran-Sanaa connection has undoubtedly grown stronger, but this is likely not unidirectional, nor is there yet ample evidence to conclude that the Houthis have become an outright tool for Iran’s advancement.
C. The Houthi Slogan
One might argue that the Houthi slogan “Death to America, death to Israel, curse the Jews, and victory for Islam” reflects the organization’s approach to Israel. But in practice this rhetoric is more of an attitude than a policy. Extrapolating from the slogan that the fundamental Houthi approach to Israel is that they intend to destroy it is not a particularly useful conclusion. To be clear, the Houthi stance toward Israel is hostile and extremely negative, but if or how this approach is operationalized is a critical subject for consideration.
A 2010 report by the RAND Corporation observes, “The hope Husayn expresses, however, is not that this slogan will incite acts of violence per se…Examining the original context of the slogan, it becomes clear that Husayn al-Houthi intended it as a rallying cry through which he could capitalize on anti-U.S. sentiment while also giving his followers a way of identifying with one another in his absence.” This decade-old assessment of the intentions behind the Houthi slogan was likely based on the fact that until that point the group prioritized its struggle against the government of Yemen and did not seek to attack American or Israeli targets directly.
Similarly, although Iran originally patented the slogan “Death to America, death to Israel,” the Islamic Republic’s leadership has not sought direct all-out confrontations with either country. In the Israeli case, Iran has cultivated relations with actors within the Arab world that are in close geographic proximity to Israel, including the Lebanese Hezbollah, Hamas in the Gaza Strip, and the Assad regime in Syria, in order to bleed as well as deter Israel. Some have even interpreted Iran’s careful phrasing of statements regarding Israel’s destruction as indicating a descriptive theological inevitability rather than a prescriptive goal to achieve as soon as possible – the reality of Tehran’s view may lie somewhere in between those two interpretations.
D. Why the Houthis Have Not Yet Attacked Israel
In recent years, the Houthis have certainly threatened to strike Israel. Nonetheless, open source material does not indicate that they have so far attempted to do so. In 2019, Houthi Minister of Defense Mohammed Nasser al-‘Atafi claimed in an interview that his forces possessed a bank of Israeli military targets. His next comment, however, was more telling, as he implied that the leadership had not yet decided to attack Israel, saying, “We will not hesitate to hit [Israel] whenever the leadership decides."
How might one understand an organization like the Houthis that has adopted hostility to Israel as a central ideological pillar but has not yet decided to operationalize those sentiments? There are several possible explanations:
- Deterrence: The Houthis may fear the potential consequences from an attack on Israel. For example, they may assess that the Israeli military response, the US reaction, and the fallout in terms of the international legitimacy of their (largely anti-Saudi) cause would be extremely costly. Therefore, they may seek to follow the Hezbollah model and instead opt for mutual deterrence vis-à-vis Israel. Houthi military spokesman Brig. Gen. Yahya al-Saree has made statements implying that the threats against Israel are essentially for deterrence purposes. He noted in a November 2019 press conference that the Israelis will suffer painful strikes – but beforehand qualified that the threat is “in the event of any direct Zionist aggression against Yemen. [Houthi forces] are completely ready to confront any threat by Israel.”
- Priority/Timing: The Houthis may have decided to put the Israel issue on hold for the time being so as to allocate their resources toward their ongoing conflicts, including the civil war in Yemen and their fight against Saudi-led intervention. A Houthi official from the political bureau explained as much on a TV interview in November 2020, when he said that the group prioritized attacking Saudi Arabia rather than Israel “since the Saudi aggressors continue their suffocating attacks against Yemen.” Alternatively, the Houthis may seek to postpone action against Israel until a future moment in which doing so satisfies a political necessity or provides an opportunity of great significance.
- Rhetoric: Anti-Israel rhetoric may serve to drum up support and divert attention from domestic problems in Yemen, but the Houthi leadership may not have any serious interest to act upon it.
- Capabilities: As Israel is 2,000 km from the Houthis’ main operational theater, launching a long-range attack while overcoming Israel’s early warning intelligence and defensive capabilities would likely prove a rather difficult task. It demands a unique force buildup effort by the Houthis that exceeds their existing capabilities. In addition, if the Houthis are thinking one step ahead, they will likely also understand the need to acquire in advance the capabilities to fend off a long and intensive Israeli response.
These possible explanations are not mutually exclusive, and more than one may inform Houthi calculations vis-à-vis Israel. It is also conceivable that there are additional reasons for the Houthi failure to strike Israel that are not publicly discernible, but weigh heavily in the group’s calculus.
Until now, the Houthis have largely targeted their external attacks at states directly involved in the Yemeni civil war, in particular Saudi Arabia and the UAE. One exception to this rule was the 2016 attempt to strike the US naval ships USS Mason and USS Ponce, off the coast of Yemen. In response to that attack, the US struck three Houthi-Saleh radar installations, and since then the Houthis have not targeted manned American assets. The US ability to thwart the Houthi attack and then deliver a firm response may indicate that it is possible for actors, toward whom the Houthis are hostile but which are not deeply and directly involved in the Yemeni war, to instill a measure of deterrence against the Houthis by effectively responding to their attacks.
E. How the Houthi Approach to Israel Could Change
It is important to consider what factors could realistically shift to make Houthi leadership more inclined to target Israel. This analysis could provide the government of Israel several indicators to watch in order to gauge the potential level of threat posed by the Houthis in Yemen. The opacity surrounding Houthi deliberations makes it difficult to speak about what might shift their calculations with any level of certainty, but nevertheless it remains important to try and identify signs that could herald a potential shift.
- One possible development that could cause Houthi policy toward Israel to become more aggressive is intensifying friction between Israel and Iran, which could occur in a number of arenas: Lebanon, Syria, Iraq, or the Iranian nuclear realm. In such a scenario, Iran could seek to improve Houthi capabilities by providing the group with advanced materiel and increased financial, intelligence, and political support, and even facilitate their activities against Israel. Tehran could go so far as to incentivize the Houthis to strike Israel by employing a variety of carrots and sticks, including calibrating support for the Houthis accordingly.
- A second possibility in which the Houthi focus shifts to target Israel is the conclusion of the current incarnation of the Yemeni civil war. If the Saudis and Houthis reach an understanding to halt hostilities and then some form of power-sharing is agreed upon within Yemen (either partition or a unified but decentralized state), the Houthis may seek to sustain continuous friction with Israel. This would serve two key purposes: first, it would maintain their “axis of resistance” bona fides and reinforce the group’s raison d'être; second, it would provide a pretext for maintaining military mobilization and avoid the potentially destabilizing consequences of demobilizing Houthi forces that would return home with military training but without promising job prospects. Organizations such as Hamas appear to have followed this route, sporadically launching pinprick rocket/missile attacks against Israel, inter alia, as a means to demonstrate that they are “doing something” against Israel, divert attention from the dismal state of affairs under their governance, and provide an excuse to maintain military mobilization.
- A third possibility is that the Houthis may view escalation on one of Israel’s other fronts, either Lebanon, Syria, or Gaza, as an opportune moment to demonstrate their commitment to declared ideological goals by striking Israel. They may do so for propaganda purposes, so as to reinforce claims of solidarity with the “resistance axis” or advocacy of the Palestinian cause. And/or they could do so to exploit practical-operational advantages, believing that Israel’s preoccupation with other fronts would curb its appetite to become involved in an intensive and possibly long-lasting conflict against a group positioned at the edge of its operational and intelligence capabilities.
- A fourth possibility is a scenario in which Israel takes on a greater role in the campaign against the Houthis in Yemen. In order to dissuade Israel from maintaining its increased support for the Saudi-led coalition, the Houthis could seek to exact a price from Israel. It is possible that such strikes against Israeli targets would unintentionally create a mutually reinforcing escalation cycle and ultimately, though inadvertently, serve to increase Israeli involvement in the Yemeni theater.
- A fifth possibility is that Israel will initiate a strike on Houthi forces as some form of pre-emptive measure against the group’s military buildup, perhaps an attempt to replicate the “campaign between wars” in the Yemeni context. This could elicit a retaliatory Houthi response.
More generally, beyond these five scenarios, the erosion of Israel’s deterrence, either due to events on other fronts or particularly vis-à-vis Houthi capabilities, could increase Houthi temptation to launch a first strike.
The question of the Houthis’ strategic approach to Israel is an important one that should inform Israeli efforts to cope with the Houthi threat. At the same time, longstanding intentions can change rapidly and without obvious warning. It is ultimately a “mystery” whether Houthi leader Abd al-Malik al-Houthi will opt to focus his efforts on striking Israel – even he himself may not be certain of how he intends to proceed.
III. Houthi Operational Capabilities and Practices
A. Long-Range Cruise Missiles, Attack UAVs, and Ballistic Missiles
The most tangible threat that the Houthis pose to Israel is undoubtedly their proven capability to direct long-range fire. That said, a sober reflection on the Houthi firepower capabilities demonstrated thus far indicates that prospects for actualizing such a threat against Israel are real but limited. In order to strike Israel the Houthis must launch munitions capable of reaching targets at least 1,600 km away – that is the shortest distance from the northernmost area of Yemen (Majz) to the southernmost point of Israel (Eilat). For practical reasons, the Houthis would likely be required to launch from considerably further south, while striking high value targets in Israel would necessitate striking considerably further north of Eilat (at least Dimona). Therefore, to pose a strategic threat to Israel, the Houthis would require munitions capable of striking at a range of at least 1,800 km.
At the present time, the primary Houthi threat against Israel is their cruise missile capability. It is uncertain but likely that a Houthi attack on Israeli territory can be carried out using the Hoveyzeh model of the Iran-made Soumar cruise missile. The Hoveyzeh is capable of striking targets at a range of about 1,350 km when operating at low altitude (a tactic used to minimize the likelihood that it will be identified and intercepted). When launched to higher altitudes and not maneuvering to evade detection or interception, the missile can apparently achieve considerably longer distances. At this stage, it is not clear whether such missiles presented by the Houthis in the context of various operational activities are produced locally or produced in Iran and smuggled piecemeal into Yemen. In any case, in recent years the Houthis have launched a number of attacks with this type of cruise missile, targeting assets of members of the Saudi-led coalition; those instances provide operational evidence of a significant Houthi capability to launch comparable precision cruise missiles strikes against Israel.
Another relatively advanced Houthi cruise missile, known as the Quds-2 (Figure 1), was reportedly used in strikes on Aramco facilities near Jeddah and Ras Tanura in Saudi Arabia; in neither attack did the missile demonstrate adequate range, only 600 km and 1350 km, respectively. Nevertheless, according to an interview with senior Houthi functionary Abd al-Wahhab al-Mahbashi, the ultimate goal of developing this weapon (named “Quds,” which is the Arabic name for Jerusalem) is essentially to strike Israel. Al-Mahbashi explained: “With regard to the targeting of the city of Jeddah, we believe that this missile [of ours] is meant to target Eilat and not Jeddah… the development and testing of this missile will continue, until we manage to reach deep into Palestinian [territory], and target the Zionist entity of the blessed Palestinian land.”
Another component of long-range Houthi firepower are UAVs, either armed with bombs for air-to-ground strikes or used as loitering munitions. The Houthis have an extensive arsenal of UAVs, including long-range Samad models. The group used Samad UAVs for long-range attacks in 2018 (Abu Dhabi) and then again in 2019 (Riyadh). However, the Samad-3, which claims an operational range of 1,800 km – theoretically enough to conduct attack on Israel – will have limited ability to inflict damage on Israeli infrastructure, given its 45 kg warhead.
In March 2021 the Houthi military industries unveiled a Samad-4 model it claims has a range of 2000 km and is capable of delivering two small payload rockets. At the same event, the Houthis presented the Wa'id UAV, which appears to be a loitering munition with a declared range of 2500 km. These latest developments indicate a potential leap forward in the Houthi arsenal of weapons capable of striking Israel.
Yet on the whole, due to various limitations of their range-capable UAVs, Houthi weapons will presumably be launched with operational characteristics (pathway, altitude, speed, and out of ground control range) that increase the likelihood of detection and interception by Israeli air defense systems. Also, as with the Samad-3, even if one such UAV were to successfully carry out an accurate strike on Israeli infrastructure, it would be capable of inflicting very limited damage due to its relatively small payload.
To maximize effect and complicate interception, the Houthis could attempt to carry out a multi-drone simultaneous strike. It is also possible that the Houthis will attempt to execute a far more complex operational plan by simultaneously launching both attack UAVs and cruise missiles at Israel. Far less likely but still possible, the Houthis might attempt to attack targets on Israeli soil with short-range UAVs, such as Samad-1, Samad-2, or Qasef, via “jumping off points” in Syria, Iraq, or Sinai; possible evidence for such intent was provided by the Houthis’ March 2021 demonstration of their newest tactical-range loitering munition, named "Khatif," hitting a target draped in an Israeli flag (Figure 2).
In contrast to their UAV arsenal, the Houthis lack any proven indigenous capabilities for the production of ballistic missiles capable of striking Israel. The relevant missiles for such a strike would be one of the Burkan-family type, which is based on the Iranian Shiab/Qiam missiles. To date, the Burkan-3 version of the missile has proved an operational range of about 1,200 km. However, that variation of the Burkan is produced through reducing the size of the warhead of the Burkan-H2 in order to extend its range, so it is not indicative of Houthi innovation or local adoption of a more advanced Iranian capability. Therefore, the central concern in this context is the possibility of a technological leap in the event that the Houthis are provided more advanced ballistic missile capabilities by Iran – particularly advanced Shihab missiles that have considerably longer ranges and would be capable of reaching Israel from Yemen. This technology is readily available for Iranian forces, particularly through the Shihab-3 missile in its MRBM version, which already has a range of 2,000 km.
Finally, it is also possible that in the future the Houthis will permit Iran’s IRGC forces to launch advanced Iranian cruise missiles, UAVs, or ballistic missiles from Yemeni territory. This could occur in a scenario in which Tehran seeks to strike Israel while distancing itself from the attack and minimizing potential blowback.
Another tangible threat to Israeli national security stems from the possibility that the Houthis will attack ships in the maritime transport lanes along the Bab al-Mandeb Strait, Red Sea, or Gulf of Aden. In recent years it has become a source of international concern, regardless of the particular Israeli issue, that the Houthis have the capability to carry out a significant campaign against maritime traffic in the area so as to disrupt the flow of goods through the Suez Canal, interrupt the global oil supply, and raise maritime insurance premiums. The group could do so under the declared pretext that this campaign is a response to Israeli policy, and they could seek to hold regional maritime commerce hostage vis-à-vis the international community to press Israel on specific policy issues.
Although this scenario is technically possible, its practical prospects for success are low. After all, this area is well-known for its risks of sabotage and piracy (Figure 3). Therefore promoting freedom of navigation around this critical maritime chokepoint has become a central aim for a growing number of naval task forces operating there (US, French, Russian, Chinese, and Egyptian). Hence, the Houthis’ ability at present to significantly disrupt maritime traffic or cause extensive damage to global shipping is limited.
If, instead, the Houthis focus their maritime efforts on establishing a direct operational threat to Israel, they would need the capability to launch a strike specifically targeting a ship that is somehow identified with Israel. Such an attack on Israeli shipping would presumably be carried out on the targeted vessel while it is transiting the 25 km-wide Bab al-Mandeb or along international shipping routes almost 100 km from the shores of the Gulf of Aden or Yemen’s Red Sea coast.
To locate and identify high-quality naval targets, in the past the Houthis employed a fleet of patrol boats. Those units played a significant role prior to 2016, and later on some coastal radar capabilities were added and integrated to this array. The radar systems deployed along Yemen’s western coast would be crucial for detecting and identifying naval asset in the area and potentially even enabling attacks on them with anti-ship missiles. But they do not entirely resolve the primary challenge to the efficacy of such steps in the Israeli context: the ability to strike Israel-related targets. In this sense, the Houthis would be forced to choose from a range of poor prospects:
- Striking an Israeli navy ship: certainly a prominent target, but quite rare in the areas accessible to the Houthis, and capable of effectively defending itself against the types of threats Houthis can mount.
- Striking a ship from a commercial fleet owned by Israel-based companies: There are only about 300 such vessels in the world, most of them do not sail along the shores of Yemen, and they fly flags of convenience, which can obscure origin and ownership.
- Striking a commercial shipping line to negatively impact the supply of goods to Israel: This would require a strike on non-Israeli ships passing Yemen on the way to Israel, most of which are Chinese-owned.
Regarding the Houthi capabilities for carrying out such an operation, the group possesses an arsenal of anti-ship missiles of varying quality and origin:
- Styx missiles: Outdated imports from the Soviet Union, produced in the 1950s, with a range of about 40 km, and capable of delivering a half-ton payload.
- Chinese C-801 missiles, upgraded C-802 (Iranian name “Noor”), with a range of about 180 km and capable of delivering a payload of about 165 kg. There is also apparently a “local” Houthi version of this missile type, which is called al-Mandab-1, although it does not seem to be produced indigenously in Yemen.
These anti-ship capabilities have already been demonstrated by the Houthis against a number of vessels belonging to the countries of the Saudi-led coalition (as well as against the American destroyer USS Mason and amphibious transport dock USS Ponce in 2016).
Anti-ship missile capabilities are supplemented by skilled Houthi naval commando units. These units are capable of commandeering ships on the open seas, as they proved when they took over Saudi and South Korean ships 33 km from the Yemeni coast in November 2019. Also, the units can carry out attacks on shipping in a variety of different formats, including: approaching and firing anti-tank missiles (as was done against the MT Muskie in May 2017), and attaching limpet mines to the hulls of ships (as appears to have been done by Iran-backed forces to the Israeli-owned ship MV Helios Ray in February 2021).
Alternatively, it is possible that Houthi forces will carry out strikes on Israeli maritime assets with “suicide ships” that are explosive and operated remotely. This could entail a multi-direction simultaneous speed boat attack, similar to the strike on the Saudi frigate al-Madinah in January 2017 and considered especially difficult for the target to defend against. These types of attacks can be conducted either via converted vessels or specially designed unmanned waterborne vehicles. In the latter case, instead of conspicuously converted "regular" boats, Israeli ships would face fast, low-profile, remote-controlled specially designed drone ships (USV) that pose a torpedo-style threat.
Another maritime threat that the Houthis already employ is the planting of naval mines in areas close to the Bab al-Mandeb Strait. In 2017, which appears to have been the peak of Houthi naval mining, 15 incidents attributed to the Houthis were recorded along a 100 km area of the Yemeni coast between the ports of Midi and Mokha (in some instances the mines were reportedly supplied by Iran). The group’s interest in further developing those capabilities is highlighted by the fact that their military industries appear to be producing more than ten types of naval mines
Still, recent years have seen the decline of this threat due to steps taken to improve maritime security in this area, including urgent mine clearance operations conducted by the Saudi navy as well as other foreign navies. The Houthis have the capability to continue and even intensify naval mining operations so as to disrupt maritime traffic and cause damage to vessels along maritime routes in this area; however, operationalizing this threat to target Israeli shipping accurately is possible but complicated, to the point of being unrealistic.
C. Operating Abroad
An additional threat to consider is the Houthi movement’s ability to conduct terror attacks against Israel within the 1948 boundaries, in the West Bank, or against Jewish or Israeli targets abroad. At the same time, despite the Houthis’ nature as a violent militia group, their modus operandi does not resemble those of a classic international terror organization. They have been, at least until now, very much a domestic-orientated movement, and have conducted very few non-aerial/non-naval operations outside of Yemen’s borders. An analysis of the attacks conducted by the Houthis indicates that out of nearly 2800 attacks between 2012 and 2019, only 300 occurred beyond Yemen’s borders (almost all in neighboring Saudi Arabia). According to available open source material, the Houthis are not expending time and resources to establish infrastructure enabling a shift to a strategy of international terror (with the possible exception of inside Saudi Arabia).
That said, one cannot rule out the possibility that the movement will “upgrade” by building an international terror network in the future. An obvious example of an organization that did so is Hezbollah, which broke the “glass ceiling” of being a local group by successfully carrying out a number of deadly attacks in South America and Europe and directing the majority of subversive activities in the West Bank over an extended period. This was achieved mainly, but not exclusively, due to the support that Iran provided, with an emphasis on resources and capacity, but its success also depended to a considerable extent on exploiting the Lebanese Shia diaspora. In seeking to replicate the Hezbollah model of launching attacks against Israeli/Jewish targets from outside of Yemen, the Houthis would face considerable challenges due to their relative shortage of resources, assessed disparities in the characteristics and depth of Iranian support for the two groups, and lack of a Yemeni-Zaydi diaspora network committed to the Houthi cause.
Further consideration of Houthi operations beyond Yemen’s borders also raises the possibility of Houthi military units being deployed to the frontlines of Israel’s other adversaries. This would, in a sense, be similar to the threat posed by Iran-backed Shia militias operating in Syria and Iraq; according to Israeli assessments, the IDF could find itself in direct conflict with those groups during a time of war along Israel’s northern front. Yet the similarity between Shia militias and Houthis is not absolute. The Houthis’ overwhelming focus, at present, on local/national issues is unlikely to lead officials to send their soldiers 2,000 km from Yemen to fight against Israel. But although that now appears unlikely, it could change over time or in "unique" strategic circumstances.
While sending Houthi forces to the Israeli front is no simple task, recent years have witnessed a variety of such “expeditionary forces” making their way to different conflict zones, including the recent example of deploying Syrian Turkmen militias a distance of 1,500 km to Libya. Yet in the Houthi case, even with Iranian logistical and operational support, this step will be laden with challenges. Nevertheless, one cannot rule out the possibility of Houthi units/cells infiltrating into the conflict zones to take part in battles against Israel due to the Houthi leadership’s order; a local initiative of prominent field commanders; or individual volunteers seeking to fight for ideological or financial reasons.
What is likely to emerge from Yemeni civil war is what we refer to as “conflict residue,” a term meant to highlight the problematic future of tens of thousands of Houthi fighters who took an active role in the insurgency/civil war since 2014 or even 2004, underwent radical ideological indoctrination, neglected other possible career paths, did not receive adequate educations, abandoned their nuclear families, and in some instances committed or were accomplices to crimes. For many thousands of these fighters, returning to the dismal labor market following years on the battlefield will be difficult or impossible; without rehabilitation mechanisms they may find themselves wandering between different conflict zones and offering their services to whomever is willing to pay (including groups hostile to Israel).
D. Indirect Friction
The final aspect of the Houthi threat worth considering is the prospect of Houthi assistance in force buildup for Israel’s adversaries, with an emphasis on Houthi support for Palestinian organizations in the Gaza Strip. In the past, at least during the period of 2014-2017, reports circulated about Iran’s possible use of the Houthis to support its efforts to provide weaponry to Palestinian organizations such as Hamas and Palestinian Islamic Jihad (PIJ). Increased activity on this axis is possible if it is used to transfer surplus Houthi weapons to Gaza in future scenarios when the fighting in Yemen dies down or Iran purchases advanced weapons for Hamas or PIJ from Houthi military industries.
Israeli adversaries operating in the Gaza Strip may demonstrate considerable interest in receiving Houthi ATGMs, UAVs, guidance systems, technological components of Houthi tactical missiles (“long-range missiles” in Gazan parlance), and anti-ship missiles. In addition, it is possible that the Palestinian terror operatives will attend training camps in Yemen to learn a wide variety of military or terrorism tactics and skills. Such acts of support by the Houthis would present the group with a convenient avenue to express their anti-Zionist/antisemitic and pro-Palestinian attitudes, provide a source of revenue, and avoid a significant risk of direct conflict vis-à-vis Israel.
Against this background, there are five key points critical to the formulation of an Israeli policy on the Houthi threat, including military force buildup efforts:
1. Despite their rhetoric, the Houthis do not appear to have taken a decision to strike Israel, and they may never decide to do so. However, strategic developments in the region, such as intensifying pressure from Iran or a shift in domestic Yemeni dynamics, could make a Houthi attack on Israel more likely. Our primary concern is that such a decision is likely to be made through an opaque process among the Houthi leadership, with no discernible signals and in an environment that has comparatively poor intelligence coverage, so it may happen suddenly and unexpectedly. Therefore, much of Israel’s focus on Yemen should be directed toward monitoring (and ideally, if necessary, limiting) Houthi capabilities.
2. As they have no real direct/concrete grievances against Israel, the Houthis’ willingness to strike Israel on behalf of Iran remains an open question. The degree to which the Houthis are an Iranian proxy will only become evident in real-time when the interests of the Houthis and Tehran diverge. The Saudis used to joke “you cannot buy a Yemeni but you can rent him for a while”; in other words, leverage derived through patronage, in this case Iranian, is not absolute and may last for a limited duration.
3. At present, the Houthis do not appear to have the capabilities to pose a major strategic threat to Israel. In the future, it is conceivable that that:
- The Houthis will build up an arsenal of weapons capable of reaching Israel’s strategic assets.
- Iran will provide a critical mass of range-capable PGMs.
- Houthi maritime warfare capabilities will advance significantly to the critical point where they are capable of posing a considerable threat to Israeli shipping.
- The Houthis prove willing to offer Yemen as a launch pad for IRGC missile units.
- The Houthis increase support to Hamas or PIJ in Gaza through the group’s indigenous military industrial production and with Iran’s encouragement.
4. Even without direct hostilities between Israel and the Houthis, developments in the Yemeni civil war could affect Israel negatively. The theater serves as a testing ground of sorts for Iranian weapon systems in conflict, and in particular their use against Western platforms. The rapid pace of improvement in Houthi capabilities, from amateurishly using RPGs in 2010 to using precision-guided missiles for well-coordinated assassination attempts in 2020, indicates a learning process that could create knowledge that is then (directly or indirectly) disseminated among other axis partners, including Hezbollah and Hamas.
5. A Houthi strike on Israel or the group’s accumulation of a disproportionate stockpile of weaponry that threatens Israel will present the Israeli leadership with a dilemma of if/when to strike – at risk of being drawn into the Yemeni quagmire. Israel will face this challenge with considerable difficulty due to operational and intelligence gaps as well as the absence of a clearly defined strategy toward Yemen, all of which limit decision makers’ ability to maneuver strategically.
Relegating the Houthi threat to “out of sight, out of mind” may allow Israel to focus its resources on more immediate challenges, but doing so is accompanied by its own set of risks.
 For Fabian Hinz’s assessment of the 2019 Houthi missile attack on Abha airport, in which he describes the Houthi leadership and missile force as a “black box,” see his “Abha Airport Missile Attack: Understanding the Houthi-Iranian Logic in Escalation,” Foreign Policy Research Institute, June 17, 2019, https://bit.ly/3a2CgWW.
 According to a tweet by Yemen expert Nadwa al-Dawsari, the Houthis executed numerous prominent tribal leaders in their territory in the early months of 2021. See https://twitter.com/Ndawsari/status/1370784445859561476?s=20.
 For the full report on infighting in Houthi territory, see “The Myth of Stability: Infighting and Repression in Houthi-Controlled Territories,” https://bit.ly/3wOiFU0.
 For an assessment of the internal machination in the Houthi organization published in 2010, see Barak Salmoni, Bryce Loidolt, and Madeleine Wells, Regime and Periphery in Northern Yemen: The Huthi Phenomenon, RAND, 2010, https://www.rand.org/pubs/monographs/MG962.html.
 On Houthi fundraising for Hezbollah, see Lizzie Porter, “Yemen’s Houthi Rebels Raise nearly $300,000 for Hezbollah,” National News, July 22, 2019, https://bit.ly/3dQdcUg.
 For an article on the Houthi attempt to swap Hamas prisoners for Saudi, see Ahmad Abu Amer, “Houthis, Hamas Merge Diplomacy around Prisoner Release,” al-Monitor, January 5, 2021, https://bit.ly/3e8EntF.
 The Houthi linked account can be found here: https://twitter.com/AShuahda/status/1356668351230148610?s=20.
 For an in-depth article on the concept of “soft war” in Iran, see E. L. Blout, “Soft War: Myth, Nationalism, and Media in Iran,” Communication Review 20, no. 3 (2017): 212-24, https://bit.ly/2RsfYHJ.
 For the statement by Houthi spokesman Mohammed Abdelsalam, see: https://twitter.com/abdusalamsalah/status/1359564631099006978?s=20.
 Founder and leader of the Houthi movement, Husayn Bad al-Din al-Houthi, who was killed by Yemeni government forces in 2004.
 Salmoni, Loidolt, and Wells, Regime and Periphery in Northern Yemen, pp. 119-20.
 Amb. Michael Oren provides an assessment of the threat posed to Israel by Iran’s regional proxies in Michael Oren, “The Coming Middle East Conflagration,” The Atlantic, November 4, 2019, https://www.theatlantic.com/ideas/archive/2019/11/israel-preparing-open-war/601285/.
 Regional expert Ehud Yaari writes for the Washington Institute regarding Iran’s “ambiguity concerning its direct role in a decisive confrontation with Israel.” For the article, see Ehud Yaari, “How Iran Plans to Destroy Israel,” Washington Institute, August 10, 2015, https://www.washingtoninstitute.org/policy-analysis/how-iran-plans-destroy-israel.
 For a 2019 Houthi propaganda clip threatening to strike Israel, see “Houthi Military Media Publishes Propaganda Video with Hebrew Subtitles Threatening Israel with Cruise Missile Attacks: ‘There Is More to Come!’” MEMRI TV, August 30, 2019, https://bit.ly/2PmlkU3.
 An article with the Defense Minister’s statements regarding Israel can be found at
"وزير دفاع اليمن يهدد بضرب أهداف اسرائيلية," قناة العالم, ٠٨ ديسمبر ٢٠١٩,https://bit.ly/3mJSut5 [in Arabic].
 For an in-depth look at Israel-Hezbollah mutual deterrence, see Daniel Sobelman, “Learning to Deter: Deterrence Failure and Success in the Israel-Hezbollah Conflict, 2006–16,” International Security 41, no. 3 (2017), https://bit.ly/3gE43kp.
 For the clip of Brig. Gen. Yahya al-Saree’s statement with English subtitles, see “Houthi Military Spokesman General Yahya Saree: If Israel Attacks Yemen, We Will Respond with "Painful Strikes" the Kind of Which It Does Not Expect,” MEMRI TV, November 20, 2019, https://bit.ly/3aGcTub.
 For the full interview with English subtitles, see “Houthi Official Abd Al-Wahhab Al-Mahbashi: We Are Developing Missiles That Can Reach Eilat, Israel; Saudi Aggression Forces Us to Target Saudi Arabia Instead,” MEMRI TV, November 24, 2020, https://bit.ly/3tWryJA.
 For a U.S. Government report on the Houthi attacks on U.S. shipping, see Jeremy Sharp, “Yemen: Recent Attacks against U.S. Naval Vessels in the Red Sea,” October 21, 2016, https://fas.org/sgp/crs/mideast/IN10599.pdf.
 It is worth noting, however, that unmanned aerial assets have been targeted on several occasions since then.
 According to Gregory Treverton’s 2007 article for RAND Corporation “Risks and Riddles,” a mystery “poses a question that has no definitive answer because the answer is contingent; it depends on a future interaction of many factors, known and unknown. A mystery cannot be answered; it can only be framed, by identifying the critical factors and applying some sense of how they have interacted in the past and might interact in the future. A mystery is an attempt to define ambiguities.” See https://www.rand.org/blog/2007/06/risks-and-riddles.html.
 See note 18.
Information in this section is based on the following report: Ian Williams and Shaan Shaikh, “The Missile War in Yemen,” CSIS, June 2020.
 The Rased and Qasef UAVs are the most relevant weapons for tactical distances.
For a more in-depth analysis of the Samad’s capability, see Mark Voskuijl, Thomas Dekkers, and Ralph Savelsberg, “Flight Performance Analysis of the Samad Attack Drones Operated by Houthi Armed Forces,” Science & Global Security 28, no.3 (2020), https://bit.ly/3nxl7KF.
 Drones of this type were already used in attack on Aramco facilities in September 2019, but despite Houthi claims of responsibility, this was likely carried out by Iran.
 Ironically, this drone, which was first seen in Iran in 2017, is probably a locally adapted version of the Israeli-designed IAI Harpy.
 A plan similar to a March 2021 strike on Saudi Arabia, which involved the launching of 15 Houthi UAVs.
 Ballistic missiles of the Qaher and Badr variety are not relevant for such distances.
 For further assessments of the Houthi means to threaten shipping routes around Yemen’s coast, see “How Much Do The Houthis Threaten Red Sea Shipping?,” Dryad Global, November 26, 2019, https://bit.ly/3dTGbrw; Ana Aguilera Raga, “The Bab el-Mandeb Strait: Geopolitical Considerations of the Strategic Chokepoint,” ieee.es, March 10, 2020, https://bit.ly/3gAUaEl.
 Defined by Merriam-Webster as “registry of a merchant ship under a foreign flag in order to profit from less restrictive regulations.”
 Attacks on Chinese-owned ships are liable to create complications for the Houthis due to their Iranian patron’s considerable economic dependence on China.
 These vessels are termed Water-Born Improvised Explosive Devices (WBIEDs). Captured models, which appear consistent with one another, are conversions of 10 meter boats made by Al Fattan Ship Industry in UAE.
 Similar to that of the Houthi Blow Fish (LPV) which was captured in the Red Sea in September 2018.
 For a report detailing the Houthis’ mining activity that year, see Shaul Shay, “The Houthi Maritime Threats in the Red Sea Basin,” Institute for Policy and Strategy, September 2017, https://bit.ly/3gG6nrg.
 There is an essential challenge of differentiating between hostile activities that include military operations and terror activities, so in this instance the authors opted to classify according to location.
 In his memoirs, a former US diplomat recounts hearing this Saudi expression. See Allen L. Keiswetter, “Interview with Allen L. Keiswetter,” April 29, 2010, https://adst.org/wp-content/uploads/2018/11/Keiswetter-Allen-L.pdf.
 For an OSINT investigation of the Houthi missile attack that nearly wiped out Yemen’s Cabinet in December 2020, see Nick Waters, “Rockets over Yemen: Inside the Houthis’ Botched Attack on Aden Airport,” Bellingcat, February 9, 2021, https://bit.ly/3vkS932.