The prospects for returning to a unified Yemen remain dim. According to the United Nations Panel of Experts on Yemen, "The authority of the legitimate Government of Yemen has now eroded to the point that it is doubtful whether it will ever be able to reunite Yemen as a single country." While the country's unity is a relatively recent historical phenomenon (dating to 1990), the international community had widely supported the reform of Yemen's political system under a unified government just a few years ago. In 2013, Yemenis from across the political spectrum convened a National Dialogue Conference aimed at reaching broad national consensus on a new political order. However, in January 2014 it ended without agreement, and the Houthis launched a war.

The situation in Yemen is considered one of the world's worst humanitarian disasters. According to the United Nations Office for the Coordination of Humanitarian Affairs (UN OCHA), out of a total population of nearly 30 million people, 22.2 million Yemenis are in need of humanitarian assistance. Since March 2015, the United States has been the largest contributor of humanitarian aid to Yemen.

In early December 2017, the Houthi-Saleh alliance unraveled, culminating in the killing of former President Saleh on December 4, 2017. Since Saleh's death, the coalition has made military gains. Nevertheless, Houthi forces remain ensconced in northern Yemen and, despite multiple attempts by the United Nations to broker a peace agreement, all sides have remained deadlocked.

Now in its fourth year, the war in Yemen has reached a critical juncture. On June 12, 2018, the Saudi-led coalition, a multinational grouping of armed forces led primarily by Saudi Arabia and the United Arab Emirates (UAE) launched Operation Golden Victory, with the aim of retaking the Red Sea port city of Hudaydah (alt. sp. Hodeidah, Al Hudaydah). The northern Yemeni armed militia and political movement known as the Houthis (Ansar Allah in Arabic) hold the city and the port, which is crucial for the importation of commercial goods and humanitarian aid into Yemen.¹

As various regional groups within Yemen vie for territory, the question of who controls Hudaydah is vital for several reasons. Hudaydah (Yemen's second-largest port after Aden) provides the mostly land-locked northern Houthi-controlled areas with access to the Red Sea. Control of Hudaydah is key to resupplying the Houthi-controlled national capital of Sanaa. The port also is north of the Bab al Mandab strait (alt. sp. Bab al Mandeb, Bab el Mendeb), one of the world's maritime chokepoints.² Hudaydah also generates revenue for the Houthis, who "tax" imports and control the distribution of food and fuel leaving the port.

Operation Golden Victory, which is spearheaded by the United Arab Emirates, arguably represents the coalition's most concerted effort to change the balance of power on the ground and regain leverage in any future political settlement of the Yemen conflict. For the coalition, retaking Hudaydah could turn the tide of the war in their favor and perhaps even facilitate their gradual disengagement from direct involvement in the conflict.

To date, the coalition has advanced to the outskirts of the city and taken most of Hudaydah airport. However, on June 23 the coalition "paused" its ground advance on the city in order to allow Martin Griffiths, the Special Envoy of the United Nations (U.N.) Secretary-General for Yemen, to negotiate a cease-fire. Hundreds of thousands of civilians remain in Hudaydah, and any urban conflict risks not only incurring high numbers of civilian casualties, but also destroying the port and thus exacerbating food shortages throughout northern Yemen. International humanitarian and aid organizations have been united in calling on the coalition to refrain from attacking Hudaydah and to keep the port open for continued shipments of food and fuel into Yemen. In early August, dozens of Yemenis died in strikes against a fish market and hospital inside Hudaydah city. The coalition has denied conducting these strikes, claiming that dozens of civilians were killed from Houthi mortar fire.³

As of late August 2018, fighting has shifted to districts surrounding the city, such as the Durahmi district and the historic area of Zabid (the town itself is listed as a UNESCO World Heritage site). Zabid rests south of Houthi-controlled Hudaydah and north of the coalition-controlled coastal town of Mocha. It is situated on an inland highway (N3) just west of the northern highlands. The coalition has conducted several air strikes near Zabid.

According to the United Nations Office for the Coordination of Humanitarian Affairs (UN OCHA), as of late August, humanitarian organizations have assisted 50,100 displaced households (over 200,000 individuals) from Hudaydah Governorate.⁴ Approximately 350,000 citizens remain in the city. Hudaydah port has remained open during the fighting, though supplies of electricity and water for residents have been disrupted. Several health facilities have closed, and USAID has provided support to the World Health Organization to increase hospital capacity within Hudaydah.⁵ Aid agencies also have warned that a cholera outbreak, which is affecting other parts of the country, could occur in Hudaydah as well (if sanitation and water infrastructure are crippled by the fighting.

Although the coalition has advanced relatively easily northward along the western Yemeni coastal plain toward Hudaydah, most observers believe that an assault on the city itself will be far more problematic. The Houthis have laid landmines on access highways leading into the city and have dug trenches, erected barricades on main roads, and taken positions overlooking the city from the highlands to the east.

Forces under the command of the UAE are leading the operation to retake Hudaydah, although actual UAE soldiers are in an advise- and-assist role. Several Yemeni militias of former soldiers and irregulars are on the front lines, including (1) Republican Guards at the command of Tariq Saleh, the nephew of the late Ali Abdullah Saleh, the longtime president of Yemen who was killed by the Houthis in 2017; (2) the Giants Brigade, a group of southern Yemenis and former Yemeni soldiers; and (3) the Tihama Resistance Forces, a local militia comprised of recent recruits. According to Jane's, these forces may be equipped with "Mine-Resistant Ambush-Protected Vehicles (MRAPs), Leclerc main battle tanks, and UAVs for intelligence, surveillance, and reconnaissance (ISR), provided by the UAE."⁶

As of August 2018, U.N. Special Envoy Martin Griffiths continues to try and broker a cease-fire and stave off a coalition assault against Hudaydah. The U.N. envoy plans on hosting consultations in Geneva on September 6 in order to move all sides toward a cease-fire.

Both the coalition and the Houthis remain deadlocked over the issue of the continued Houthi military presence in major urban areas such as Hudaydah and Sanaa. The coalition continues to insist that the Houthis abide by United Nations Security Council Resolution (UNSCR) 2216⁷ (April 2015), which, among other things, demanded that the Houthis withdraw from all areas seized during the current conflict. The Houthis insist on remaining in seized territory, but have expressed a willingness to allow the United Nations to operate the port of Hudaydah. Houthi leader Abdel Malik al Houthi said, "We told the UN envoy, Martin Griffiths, that we are not rejecting the role of supervision and logistics that the UN wants to hold in the port, but on the condition that the aggression against Hudaydah stops."⁸

To date, the United States government has supported the mediation efforts of Special Envoy Griffiths while reportedly refusing to increase support to assist Operation Golden Victory.⁹ As the coalition prepared to launch its initial assault on the outskirts of Hudaydah, U.S. Secretary of State Michael R. Pompeo issued a press statement noting "I have spoken with Emirati leaders and made clear our desire to address their security concerns while preserving the free flow of humanitarian aid and life-saving commercial imports. We expect all parties to honor their commitments to work with the UN Office of the Special Envoy of the Secretary General for Yemen on this issue, support a political process to resolve this conflict, ensure humanitarian access to the Yemeni people, and map a stable political future for Yemen."¹⁰

Administration officials reportedly did not respond positively to coalition requests for additional U.S. military aid in support of Operation Golden Victory (for more on U.S. involvement with and support for coalition efforts, see "Saudi Arabia and U.S. Support for the Coalition" below). According to the Wall Street Journal, U.S. Secretary of Defense James Mattis "has privately expressed reservations about the looming operation…. and has voiced concerns that a protracted assault on the port could worsen the humanitarian crisis and undercut American counterterrorism operations in Yemen."¹¹ In early June 2018, an unnamed White House National Security Council staffer told Reuters that "The United States has been clear and consistent that we will not support actions that destroy key infrastructure or that are likely to exacerbate the dire humanitarian situation that has expanded in this stalemated conflict…. We expect all parties to abide by the Law of Armed Conflict and avoid targeting civilians or commercial infrastructure."¹²

The United States has thus far rejected requests by the UAE for logistics, intelligence, and mine-sweeping operations. According to Pentagon spokesman Marine Major Adrian Rankine Galloway, "'We are not directly supporting the coalition offensive on the port of Hodeida…. The United States does not command, accompany or participate in counter-Houthi operations or any hostilities other than those authorized' against al-Qaida and Islamic State militants in Yemen."¹³ In its semiannual War Powers letter to Congress, the Administration explained its actions as being restricted to counterterrorism operations and noncombat support to the coalition:

A small number of United States military personnel are deployed to Yemen to conduct operations against al-Qa'ida in the Arabian Peninsula (AQAP) and ISIS-Yemen. The United States military continues to work closely with the Government of Yemen and regional partner forces to dismantle and ultimately eliminate the terrorist threat posed by those groups. Since the last periodic update report, United States Armed Forces conducted a number of airstrikes against AQAP operatives and facilities in Yemen, and supported the United Arab Emirates- and Yemen-led operations to clear AQAP from Shabwah Governorate. United States Armed Forces also conducted airstrikes against ISIS targets in Yemen. United States Armed Forces, in a non-combat role, have continued to provide military advice and limited information, logistics, and other support to regional forces combatting the Houthi insurgency in Yemen. United States forces are present in Saudi Arabia for this purpose.¹⁴

Some Members of Congress have expressed concern over the possibility of a siege of Hudaydah. On June 12, nine Senators wrote a letter to Secretary of State Pompeo and Secretary of Defense Mattis saying "We are concerned that pending military operations by the UAE and its Yemeni partners will exacerbate the humanitarian crisis by interrupting delivery of humanitarian aid and damaging critical infrastructure. We are also deeply concerned that these operations jeopardize prospects for a near-term political resolution to the conflict."¹⁵ Several weeks later, Senator Robert Menendez, the ranking member on the Senate Foreign Relations Committee, placed a hold on a potential U.S. sale of precision guided munitions to Saudi Arabia and the United Arab Emirates. In a June 28 letter to Secretary of State Pompeo and Secretary of Defense Mattis, Senator Menendez said, "I am not confident that these weapons sales will be utilized strategically as effective leverage to push back on Iran's actions in Yemen, assist our partners in their own self-defense, or drive the parties toward a political settlement that saves lives and mitigates humanitarian suffering…. Even worse, I am concerned that our policies are enabling perpetuation of a conflict that has resulted in the world's worst humanitarian crisis."¹⁶ In August 2018, other Members have written letters to U.S. officials seeking updates on the situation in Hudaydah.¹⁷

Since 2016, the Houthis have periodically targeted commercial and military vessels transiting and patrolling the Red Sea using naval mines, rocket-propelled grenade launchers, anti-ship missiles, and waterborne improvised explosive devices (WBIEDs). Some of the weapons used reportedly have been supplied by Iran, including sea-skimming coastal defense cruise missiles.¹⁸ As the Saudi-led coalition has advanced along the Red Sea coast toward Hudaydah, the Houthis have repeatedly threatened to increase the frequency of their attacks against commercial shipping vessels in the Red Sea.¹⁹

On July 24, 2018, the Houthis targeted two Saudi oil tankers in the Red Sea, damaging one of them. A day later, Saudi Aramco (the national oil company) suspended all oil shipments through the Bab al Mandab Strait, causing shipment delays and a modest, temporary spike in oil prices.²⁰ Days later, the Houthis announced that they would unilaterally halt maritime operations for "a limited time period." Soon thereafter, Saudi Aramco resumed shipments through the Bab al Mandab, though it is unclear what provoked the Houthis to halt additional anti-ship strikes. On August 7, Iran's state-owned media outlet reported that one Islamic Revolutionary Guard Corps (IRGC) general said "We (IRGC) told Yemenis [Houthi rebels] to strike two Saudi oil tankers, and they did it."²¹ Israeli Prime Minister Benjamin Netanyahu warned that "If Iran will try to block the straits of Bab al-Mandeb, I am certain that it will find itself confronting an international coalition that will be determined to prevent this, and this coalition will also include all of Israel's military branches."²²

On August 9, 2018, then-Commander of United States Central Command (CENTCOM) General Votel stated that

the Bab-el-Mandeb is open for business, as far as we're concerned. And I would say it's a major -- it's a major waterway, not just for the United States, but for many countries in terms of moving through that particular area. So one of our key missions here is to ensure freedom of navigation, freedom of commerce, and we will continue to exercise that through the region.²³

In March 2018, Martin Griffiths of the United Kingdom assumed the role of Special Envoy of the United Nations (U.N.) Secretary-General for Yemen, replacing Ismail Ould Cheikh Ahmed, who was unable to make headway toward a peace deal, despite multiple attempts. Ahmed ultimately blamed the Houthis for obstructing peace, declaring that their inability to make concessions on security arrangements was the key stumbling block in negotiations.²⁴ On March 15, the U.N. Security Council issued a presidential statement on Yemen, which, among other things, welcomed Griffiths's appointment while calling "upon all parties to the conflict to abandon pre-conditions and engage in good faith with the UN-led process."²⁵

In January 2018, the United Nations Panel of Experts on Yemen concluded that Iran was in noncompliance with UNSCR 2216 for failing to prevent the transfer to Houthi forces of Iranian-made short-range ballistic missiles.²⁶ On February 26, 2018, Russia vetoed a draft U.N. Security Council resolution that would have expressed U.N. concern that Iran is in noncompliance with the international arms embargo created by UNSCR 2216. The Security Council did pass a new resolution (UNSCR 2402) that renewed for a year U.N. sanctions first imposed by UNSCR 2140 (2014), such as a travel ban and asset freeze on designated Houthi leaders and the former (and now deceased) President Ali Abdullah Saleh. UNSCR 2402 also renewed the arms embargo against Yemen, first imposed by UNSCR 2216.

Although Houthi militia forces most likely do not depend on Iran for all of their armaments, financing, and manpower, many observers agree that Iran²⁷ and its Lebanese ally Hezbollah have aided Houthi forces with advice, training, and arms shipments.²⁸ In 2016, one unnamed Hezbollah commander interviewed about his group's support for the Houthis remarked "After we are done with Syria, we will start with Yemen, Hezbollah is already there.... Who do you think fires Tochka missiles into Saudi Arabia? It's not the Houthis in their sandals, it's us."²⁹ In repeated public statements by high-level Saudi officials, Saudi Arabia has cited Iran's illicit support for the Houthis as proof that Iran is to blame for the Yemen conflict. Reports and allegations of Iranian involvement in Yemen have become more frequent as the war has continued, and from Iran's perspective, aiding the Houthis would seem to be a relatively low-cost way of keeping Saudi Arabia mired in the Yemen conflict. However, Iran had few institutionalized links to the Houthis before the civil conflict broke out in 2015, and questions remain about the degree to which Iran and its allies can control or influence Houthi behavior. Iranian aid to the Houthis does not match the scale of its commitments to proxies in other parts of the Middle East, such as in Syria, Lebanon, and Iraq.

Prior to the 2015 conflict, the central government in Yemen had acquired variants of Scud-B missiles from the Soviet Union and North Korea. The Houthis took control of these missiles as part of their seizure of the capital. Since 2016, the Houthis have been firing what they call the "Burkan" short-range ballistic missile (claimed range of 500-620 miles) into Saudi Arabia (the latest version is the Burkan-2H). In November 2017, after the Houthis fired a Burkan-2H deep into Saudi Arabian territory, the Saudi-led coalition and U.S. officials said that the Burkan-2H is an Iran-manufactured Qaim missile.³⁰ In a hearing before the House Armed Services Committee, Commander of United States Central Command (CENTCOM) General Votel remarked as follows:

Certainly, as we've seen with Ambassador Haley and her demonstration, most recently, with some of the items recovered from Saudi Arabia, these weapons pose the threat of widening the conflict out of ... Yemen and, frankly, put our forces, our embassy in Riyadh, our forces in the United Arab Emirates at risk, as well as our partners'.... As we look at places like the Bab-el-Mandeb, where we see the introduction of coastal defense cruise missiles, some that have been modified, we know these are not capabilities that the Houthis had. So they have been provided to them by someone. That someone is Iran.³¹

In the summer of 2018, the United Nations Panel of Experts on Yemen provided a confidential report to the United Nations Security Council suggesting that Iran may be continuing to violate the international arms embargo by supplying the Houthis with advanced weaponry. After the U.N. experts visited Saudi Arabia and inspected debris from missiles fired by the Houthis, their report noted that these weapons showed "characteristics similar to weapons systems known to be produced in the Islamic Republic of Iran" and that there was a "high probability" that the missiles were manufactured outside of Yemen, shipped in sections to the country, and reassembled by the Houthis.³²

In May 2018, the U.S. Department of the Treasury's Office of Foreign Assets Control (OFAC) designated five Iranian individuals who have "provided ballistic missile-related technical expertise to Yemen's Houthis, and who have transferred weapons not seen in Yemen prior to the current conflict, on behalf of the Islamic Revolutionary Guard Corps-Qods Force (IRGC-QF)."³³

For Saudi Arabia, according to one prominent analyst, the Houthis embody what Iran seeks to achieve across the Arab world: that is, the cultivation of an armed nonstate, non-Sunni actor who can pressure Iran's adversaries both politically and militarily (akin to Hezbollah in Lebanon).³⁴ Well before the current conflict began in 2015, Saudi Arabia supported the central government of Yemen in various military campaigns against a Houthi insurgency which began in 2004.³⁵

In 2014, when Houthi militants took over the capital and violated several power-sharing arrangements, Saudi leaders expressed increasing alarm about Houthi advances. In March 2015, after President Hadi, who had fled to Saudi Arabia, appealed for international intervention, Saudi Arabia quickly assembled an international coalition and launched a military offensive aimed at restoring Hadi's rule and evicting Houthi fighters from the capital and other major cities.³⁶ Saudi-led coalition forces began conducting air strikes against Houthi-Saleh forces and imposed strict limits on sea and air traffic to Yemen.

From the outset, Saudi leaders sought material and military support from the United States for the campaign, and in March 2015, President Obama authorized "the provision of logistical and intelligence support to GCC-led military operations," and the Obama Administration announced that the United States would establish "a Joint Planning Cell with Saudi Arabia to coordinate U.S. military and intelligence support." U.S. CENTCOM personnel were deployed to provide related support, and U.S. mid-air refueling of coalition aircraft began in April 2015.³⁷

In the three years since, the Saudi military and its coalition partners have provided advice and military support to a range of pro-Hadi forces inside Yemen, while waging a persistent air campaign against the Houthis and their allies. Saudi ground forces and Special Forces have conducted limited cross-border operations, and Saudi naval forces limit the entry and exit of vessels from Yemen's ports (see "Restrictions on the Flow of Commercial Goods and Humanitarian Aid" below). Separately, a United Nations Verification and Inspection Mechanism (UNVIM) has operated since May 2016 to assist in validating commercial sea and air traffic in support of the arms embargo imposed by Resolution 2216.

Since 2015, the conduct of the Saudi-led air campaign against the Houthis, and U.S. support for its continual operation, has drawn widespread international scrutiny for targeting civilian infrastructure and killing thousands of Yemeni noncombatants. Critics charge that Saudi Arabia in particular should be held accountable for violating international humanitarian law by continually failing to distinguish between combatant targets and innocent civilians. According to the U.N. High Commissioner for Human Rights (UNHCHR), since the conflict began in March 2015 through August 9, 2018, the United Nations has documented "a total of 17,062 civilian casualties—6,592 dead and 10,470 injured. According to (UNHCHR), the majority of these casualties—10,471—were as a result of airstrikes carried out by the Saudi-led Coalition."⁴⁰

Since March 2015, some of the deadliest Saudi-led coalition air strikes include the following:

• September 2015: Saudi-led coalition air strike hit a wedding party, killing at least 81 civilians;
• March 2016: Saudi-led coalition air strikes hit a market in northwestern Yemen, killing at least 97 civilians and about 10 Houthi fighters;
• October 2016: Saudi-led coalition air strike hit a funeral hall in Sanaa, killing between 130 and 150 people;
• December 2017: In one day, a Saudi-led coalition air strike hit a market in Ta'izz province, killing 54 people, while a second strike killed 14 members of one family in Hudaydah province;
• April 2018: Saudi-led coalition air strike hit a wedding party in Hajjah province, killing more than 20 people;
• August 2018: Saudi-led coalition air strike hit a bus in a market near Dahyan, Yemen, in the northern Sa'dah governorate adjacent to the Saudi border, killing 51 people, 40 of whom were children. The coalition claimed that its air strike was a "legitimate military operation" conducted in response to a Houthi missile attack on the Saudi city of Jizan a day earlier that killed a Yemeni national in the kingdom.

Saudi officials acknowledge that some of their operations have inadvertently caused civilian casualties, while maintaining that their military campaign is an act of legitimate self-defense because of their Yemeni adversaries' repeated, deadly cross-border attacks, including ballistic missile attacks. Saudi strikes have focused on missile-related targets, suspected Houthi fighting units and locations, and senior Houthi leaders. At times, the coalition's Joint Incidents Assessment Team (JIAT) has reviewed air strikes in which civilian casualties were reported. According to one report, in September 2017, the JIAT had uncovered "mistakes in only three of 15 incidents it reviewed, and maintained that the coalition had acted in accordance with international humanitarian law."⁴¹ Critics have not accepted such justifications as sufficient. According to one former U.S. official who advised the Saudi government when it launched the JIAT, "It's not enough for them to identify problems. You have to make changes to operations."⁴²

In response to concerns about civilian casualties resulting from Saudi air strikes, the Obama Administration withdrew U.S. personnel from the joint U.S.-Saudi planning cell in June 2016, and later announced that it would suspend planned sales of precision guided munitions to Saudi Arabia.⁴³ In 2017, President Trump announced his intention to proceed with the suspended munitions sales and, after a policy review, directed his Administration "to focus on ending the war and avoiding a regional conflict, mitigating the humanitarian crisis, and defending Saudi Arabia's territorial integrity and commerce in the Red Sea."⁴⁴ U.S. officials continue to speak in clear terms about what they view as the importance of avoiding civilian casualties and reaching a negotiated solution to the crisis. Still, the Administration's posture on Yemen appears to reflect, to some extent, its policy of placing maximum economic and regional pressure on Iran in order to roll back Iran's regional influence.

However, as coalition air strikes have continued to result in civilian casualties, there has been a growing chorus of criticism directed against the U.S. government for its facilitation of the coalition's air campaign. Some lawmakers have suggested that U.S. arms sales and military support to the coalition have enabled alleged violations of international humanitarian law, while others have argued that U.S. support to the coalition improves its effectiveness and thus helps minimize civilian casualties. In support of that latter position, Secretary of State Michael Pompeo has testified before Congress that "It is this administration's judgment that providing [precision guided munitions] actually decreases the risk to civilians."⁴⁵ Congress has considered but has not enacted proposals to curtail or condition U.S. defense sales to Saudi Arabia, and has conditioned the use of some U.S. funds for some coalition support operations.⁴⁶

In February 2018, the Acting Department of Defense General Counsel wrote to Senate leaders describing the extent of current U.S. support, and reported that "the United States provides the KSA-led coalition defense articles and services, including air-to-air refueling; certain intelligence support; and military advice, including advice regarding compliance with the law of armed conflict and best practices for reducing the risk of civilian casualties."⁴⁷ In-flight refueling to the militaries of Saudi Arabia and the United Arab Emirates (UAE) is conducted pursuant to the terms of bilateral Acquisition and Cross Servicing Agreements (ACSAs) between the Department of Defense and the respective ministries of each country.⁴⁸

In subsequent testimony before Congress, U.S. defense officials have noted that while the United States refuels Saudi aircraft and provides advice on targeting techniques, CENTCOM does not track coalition aircraft after they are refueled and does not provide advice on specific targets.⁴⁹ U.S. refueling support may enable Saudi and coalition aircraft to remain over Yemeni airspace for prolonged periods of time. This may give coalition forces an opportunity to gather additional intelligence to improve the precision of strikes, but also may create opportunities to conduct so-called "dynamic" strikes against emergent, nonfixed targets for which detailed strike preparations and assessments have not been made.⁵⁰ In an April 2018 Senate Foreign Relations Committee hearing on Yemen, Robert S. Karem, Assistant Secretary of Defense for International Security Affairs, responded to questions on the U.S. role in the Saudi-led coalition's air campaign:

It's correct that we do not monitor and track all of the Saudi aircraft aloft over Yemen. We have limited personnel and assets in order to do that and CENTCOM's focus [sic] on our own operations in Afghanistan in Iraq and in Syria….I think the assessment of our Central Command is that the Saudi and Emirati targeting efforts have improved with the steps that they have taken. We do not have perfect understanding, because we're not using all of our assets to monitor their aircraft. But we do get reporting from the ground on what is taking place inside Yemen.⁵¹

That same month, when faced with similar questions on Saudi targeting practices in Yemen, General Joseph F. Dunford, Jr., Chairman of the Joint Chiefs of Staff, said the following:

I think mitigating the risk of civilian casualties with strikes is probably two issues. There's a cultural issue, and then there's a technical issue. And I think we've had a positive impact with the Saudis in both regards, by the advising and assisting we have been doing. We are co-located with them in their operations centers, to help them develop the techniques and tactics that will allow them to conduct strikes while mitigating civilian casualties. And I also think there's been a positive effect of the relationship that we've built with the Saudis over time, and the training, to effect the changes in the culture that would have them take that into account when conducting military operations. So it's a long, plodding process…. but I think it's paying dividends over time.⁵²

In August 2018, in response to a media inquiry on U.S. support for the Saudi air campaign, U.S. Defense Secretary James Mattis said the following:

We do not do dynamic targeting for them, where they're in the air and they come under fire with missiles being fired, that sort of thing, and they're turning on late-breaking intelligence. We try to assist them in how they protect certain locations, that sort of thing.⁵³

One of the key aspects of United Nations Security Council Resolution (UNSCR) 2216 is that it authorizes member states to prevent the transfer or sale of arms to the Houthis and also allows Yemen's neighbors to inspect cargo suspected of carrying arms to Houthi fighters. In March 2015, the Saudi-led coalition imposed a naval and aerial blockade on Yemen, and ships seeking entry to Yemeni ports required coalition inspection, leading to delays in the off-loading of goods and increased insurance and related shipping costs. Since Yemen relies on foreign imports for as much as 90% of its food supply, disruptions to the importation of food exacerbate already strained humanitarian conditions resulting from war.

In order to expedite the importation of goods while adhering to the arms embargo, the European Union, Netherlands, New Zealand, the United Kingdom, and the United States formed the U.N. Verification and Inspection Mechanism (UNVIM), a U.N.-led operation designed to inspect incoming sea cargo to Yemen for illicit weapons. UNVIM, which began operating in February 2016, can inspect cargo, while also ensuring that humanitarian aid is delivered in a timely manner.

However, Saudi officials argue that coalition-imposed restrictions and strict inspections of goods and vessels bound for Yemen are still required because of Iranian weapons smuggling to Houthi forces. Saudi officials similarly argue that the delivery of goods to ports and territory under Houthi control creates opportunities for Houthi forces to redirect or otherwise exploit shipments for their material or financial benefit.⁵⁵

After a Houthi-fired missile with alleged Iranian origins landed deep inside Saudi Arabia in November 2017, the coalition instituted a full blockade of all of Yemen's ports, including the main port of Hudaydah, exacerbating the country's humanitarian crisis. The White House issued four press statements on the conflict between November 8 and December 8, including a statement on December 6 in which President Trump called on Saudi Arabia to "completely allow food, fuel, water, and medicine to reach the Yemeni people who desperately need it. This must be done for humanitarian reasons immediately."⁵⁶

On December 20, 2017, the Saudi-led coalition announced that it would end its blockade of Hudaydah port for a 30-day period and permit the delivery of four U.S.-funded cranes to Yemen to increase the port's capability to off-load commercial and humanitarian goods.⁵⁷ The next day, the White House issued a statement welcoming "Saudi Arabia's announcement of these humanitarian actions in the face of this major conflict."⁵⁸

As a key member of the Saudi-led coalition, the UAE has focused its intervention in Yemen on the southern and western Yemeni coasts, where UAE Special Forces have allied themselves with various local powerbrokers in order to retake territory seized either by the Houthis or Al Qaeda in the Arabian Peninsula (AQAP). Unlike Saudi Arabia, the UAE has sought relationships with southern separatist groups and has nominally distanced itself both from Yemen's main Sunni Islamist party (Al Islah) and from President Hadi himself. The UAE has lost more than 100 soldiers in the Yemen operation, to date.

In the southern port city of Aden, forces allied with President Hadi have repeatedly clashed with southern separatists who have received backing from the UAE. Hadi-UAE tensions are multifaceted, as the sides disagree over how closely to embrace Al Islah and how closely to work with southern separatists, who seek either greater southern autonomy or the restoration of an independent state in southern Yemen. In the spring of 2017, the UAE supported Yemeni General Aidarous al Zubaidi's formation of the Southern Transitional Council (STC) after Hadi dismissed him as Aden's governor.

Although President Hadi has temporarily relocated Yemen's internationally recognized government to the port city of Aden, the United Arab Emirates (UAE) effectively controls the city through the presence of its own troops or allied tribal militia (known as the Southern Belt or Al Hizam in Arabic). The UAE controls Aden's airport and seaport, and has invested in rebuilding infrastructure. President Hadi's only personally loyal military force in Aden is the Presidential Protection Force, which reportedly is relatively small compared to UAE-allied forces.⁵⁹

Periodic clashes between pro-Hadi forces and UAE-backed forces have occurred, and in January 2018, the STC seized control of most of Aden from Hadi's troops in just three days. The UAE and Saudi Arabia intervened in order to ensure that the STC remains committed to the larger fight against the Houthis. After the fighting subsided, the STC declared that it would remain committed to the coalition's military operations against the Houthis and handed back military installations to Hadi's forces. Nevertheless, it appears that Hadi has a government in name only and that, on the ground, power resides in the hands of the STC.

Amnesty International has charged the UAE and Yemeni forces loyal to the Emirates with running clandestine prisons in the south where detainees have been tortured. Amnesty International also has documented cases of enforced disappearance.⁶⁰ UAE officials have denied these allegations. Section 1274 of the FY2019 NDAA (H.R. 5515/P.L. 115-232) requires the Secretary of Defense to conduct a review of related allegations and report to the congressional defense committees within 120 days.

The United Arab Emirates also has played a key role in countering AQAP throughout southern Yemen through both direct military intervention and the buildup of local proxies to hold territory liberated from AQAP. In April 2016, U.S. Special Operations Forces in Yemen reportedly worked with the UAE to defeat AQAP fighters at the port of Mukalla. As part of that operation, the UAE formed a local militia known as the Hadrami Elite Forces, who continue to receive salaries from the Emirates in exchange for holding the coastal town. UAE personnel also have trained, equipped, and paid a 3,000-man provincial militia in Shabwa governorate called the Shabwani Elite Forces to combat local AQAP militants.⁶¹ The UAE claims that it has "trained and equipped some 60,000 Yemeni fighters, 30,000 of whom were directly involved in the fight against Al-Qaeda."⁶² However, according to one Associated Press report, the UAE also has paid fighters from Ansar al Sharia (designated by the State Department in 2012 as an alias for AQAP) to join UAE-backed Yemeni groups.⁶³ In response to this report, one UAE general remarked, "You can't kill your way to victory against AQAP in Yemen with drones and SF [special forces] raids…. Ultimately, it's a competition for the people's support."⁶⁴

According to the United Nations Office for the Coordination of Humanitarian Affairs (UN OCHA), out of a total population of nearly 30 million people, 22.2 million Yemenis are in need of humanitarian assistance. Although food is available to purchase in markets, the war has devastated the Yemeni economy. Government employees have gone unpaid, and the currency has depreciated significantly (losing 126% of its prewar value). Food prices have skyrocketed, with the World Food Program reporting in May 2018 that the national average retail prices of wheat flour, sugar, vegetable oil, and red beans were 60%, 42%, 39%, and 104% higher than in the prewar period, respectively.⁶⁵ As a result of food becoming unaffordable for many Yemenis, UN OCHA reports that 17.8 million are food insecure and 8.4 million people are severely food insecure and at risk of starvation.⁶⁶

Yemen also is experiencing the world's largest ongoing cholera outbreak. The World Health Organization (WHO) estimates that from late April 2017 to July 2018, there have been 1,115,378 suspected cholera cases and 2,310 associated deaths.⁶⁷ Cholera is a diarrheal infection that is contracted by ingesting food or water contaminated with the bacterium Vibrio cholerae. Yemen's water and sanitation infrastructure have been devastated by the war. Basic municipal services such as garbage collection have deteriorated and, as a result, waste has gone uncollected in many areas, polluting water supplies and contributing to the ongoing cholera outbreak. In addition, international human rights organizations have accused the Saudi-led coalition of conducting air strikes that have unlawfully targeted civilian infrastructure, such as water wells, bottling facilities, health facilities, and water treatment plants. UN OCHA reports that 16 million Yemenis currently lack access to safe water and sanitation. In August 2018, Yemeni authorities launched an oral cholera vaccination campaign, which has vaccinated 375,000 people since it began.

On April 3, 2018, the United Nations, Switzerland, and Sweden cohosted a high-level pledging conference in Geneva to fund the U.N.'s 2018 Humanitarian appeal, which aims to raise $2.96 billion. Donors pledged approximately $2 billon at the conference, $930 million of which came from the combined pledges of Saudi Arabia and the UAE. The United States pledged $87 million and urged "all parties to this conflict to allow unhindered access for all humanitarian and commercial goods through all points of entry into Yemen and throughout the country to reach the Yemenis in desperate need."⁶⁸

As the Saudi-led coalition's campaign against the Houthis continues and Yemen fragments, the United States not only has sustained counterterrorism operations against Al Qaeda in the Arabian Peninsula (AQAP) and various affiliates of the Islamic State, but also markedly increased the tempo of strikes in 2017, though 2018 has seen a relative slowdown. According to the Long War Journal and using data provided to it by CENTCOM, in 2018, U.S. strikes in Yemen have "decreased precipitously from last year's record high of 131, which was more than the previous four years combined. At the current rate, roughly half as many will be conducted this year. That said, with 31 strikes thus far in 2018, the United States is on pace to surpass the strike total for each previous year, except 2017."⁶⁹

Some observers contend that AQAP's power inside Yemen has diminished considerably as a result of losses sustained from U.S. counterterrorism operations and of competing Yemeni factions vying for supremacy. According to Gregory D. Johnsen, resident scholar at the Arabia Foundation, "AQAP is weaker now than it has been at any point since it was formed in 2009."⁷⁰

In August 2018, U.S. officials claimed that one of the most high-value targets in the AQAP organization, bombmaker Ibrahim al Asiri, had been killed in a U.S. air strike last year. Asiri was a Saudi national who was believed to have created the explosive devices used in the 2009 Christmas Day attempted bombing of Northwest Airlines Flight 253, in a 2009 attack against former Saudi Arabian intelligence chief Mohammed bin Nayef, and in the October 2010 air cargo packages destined for Jewish sites in Chicago.

To date, two American soldiers have died in the ongoing U.S. counterterrorism campaign against AQAP and other terrorists inside Yemen. In January 2017, Ryan Owens, a Navy SEAL, died during a counterterrorism raid in which between 4 and 12 Yemeni civilians also were killed, including several children, one of whom was a U.S. citizen. The raid was the Trump Administration's first acknowledged counterterror operation. In August 2017, Emil Rivera-Lopez, a member of the elite 160th Special Operation Aviation Regiment, died when his Black Hawk helicopter crashed off the coast of Yemen during a training exercise.

The Saudi and Emirati offensive against Hudaydah would seem to represent the coalition's determination to deliver a decisive blow to the Houthis in order to allow for the Gulf monarchies to gradually wind down war operations. To date, the coalition is proceeding methodically, choosing a strategy of encirclement around the port city in order to bring maximum pressure to bear on Houthi forces remaining inside Hudaydah. At the same time, it also appears that the coalition is keenly aware of the international community's broad desire to keep the port itself functional in order to stave off further humanitarian suffering.

Whether the coalition can militarily isolate the Houthis in Hudaydah is unclear. Throughout the conflict, the Houthis have demonstrated a willingness to incur losses without compromising their goal to dominate northern Yemen. Nevertheless, the coalition appears to be positioning a range of land, air, and sea assets on the outskirts of the city, and if Martin Griffiths, the Special Envoy of the United Nations (U.N.) Secretary-General for Yemen, is unable to convene negotiations for a cease-fire, the likelihood of an all-out assault on Hudaydah could increase.

No end to the conflict appears imminent, either through total victory of one side or a compromise solution. The willingness of parties to the conflict, including U.S. partners, to potentially accept less than fully preferred outcomes is not publicly known. Iran, now involved in Yemen in new ways, may prove unwilling to sever ties that vex its Saudi adversaries. Political and military compromise between the coalition and the Houthis could bring fighting to an end, but might also entrench a hostile Houthi movement as a leading force in a new order in Yemen. Further intransigence and aggressive pursuit of maximalist goals by the parties might eventually tip the balance in favor of once side or the other, but would likely impose chronic costs on U.S. partners and lead to continued humanitarian suffering.

The United States has few good choices in Yemen. For the Trump Administration, U.S. officials have supported the continued defense of Saudi Arabia against Houthi missile and rocket strikes, while also openly calling on coalition members to use air power judiciously to minimize civilian casualties. The Administration has argued against congressional attempts to block arms sales or condition U.S. assistance, arguing that continued U.S. assistance is more likely to achieve the objective of limiting civilian casualties and maintaining strategic ties to Gulf partners than a punitive approach. So far, the United States has refrained from providing direct support to the coalition's offensive against Hudaydah. If, however, the coalition attacks inside the city, the Administration could find itself in the difficult position of having to choose between supporting the coalition's attempt to combat the Houthis, an Iranian ally, or being seen as complicit in the further humanitarian suffering of the Yemeni civilian population at the hands of both the Houthis and Saudi-led coalition forces.

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