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Updated July 12, 2024
Yemen: Conflict, Red Sea Attacks, and U.S. Policy
Yemen is a conflict-afflicted nation along the strategic Bab
Arab Spring-era protests and unrest led the president of the
al Mandab Strait, one of the world’s most active shipping
Republic of Yemen Government (ROYG) to resign in
lanes. Since 2015, a civil war has pitted the Iran-backed
2012. A U.N.-mediated transition and national dialogue
Houthi movement against Yemen’s internationally
sought to broker new governing arrangements. The Houthi
recognized government, its backers, and other anti-Houthi
movement (alt. Ansar Allah or Partisans of God), a north
forces. Foreign intervention complicates the conflict, which
Yemen-based Zaydi Shia network, opposed U.N.-backed
has contributed to what United Nations agencies have
outcomes and resumed an insurgency. In 2014, the Houthis
described as “one of the largest humanitarian crises in the
seized the capital, Sana’a, and later advanced on Aden.
world.” An uneasy truce has frozen conflict lines since
ROYG leaders fled and requested international
2022 (Figure 1). The Iran-backed Houthis have launched
intervention. In March 2015, a coalition led by Saudi
numerous attacks on international shipping since October
Arabia began a military campaign against the Houthis,
2023, ostensibly to compel Israel to end its war with
whose attacks across Yemen’s borders grew in complexity
Hamas. U.S.-led coalition patrol operations and
and scope with deepening support over time from Iran. The
counterstrikes seek to restore security in the Red Sea
United States has provided logistical, intelligence, and
corridor, but Yemen’s underlying conflict remains
advisory support to the coalition, but ended aerial refueling
unresolved and the long-term threats the Houthis could pose
and some arms sales to Saudi Arabia in response to civilian
present a vexing challenge for policymakers to consider.
casualties and congressional action.
Overview and Key Stakeholders
In 2019, tensions between anti-Houthi forces in the ROYG
Long-running Yemeni disputes over governance and energy
(backed by Saudi Arabia) and the separatist Southern
resources have deepened since 2015 amid foreign influence
Transitional Council (STC, backed by the United Arab
and intervention. The Republic of Yemen was formed by a
Emirates) led to open warfare. A 2020 power-sharing
1990 merger of the Sana’a-led Yemen Arab Republic (a
agreement formed a coalition government. Since 2022, an
former Ottoman province, then Zaydi Shia-ruled kingdom)
eight-person Presidential Leadership Council (PLC) has led
and the Aden-led People’s Democratic Republic of Yemen
Yemen’s internationally recognized government. That year,
(a former British colony and protectorate, then independent
the ROYG and Houthis signed a truce, halting military
Marxist regime). North-south tensions and conflict have
operations and establishing humanitarian measures. Lines
recurred since the 1960s, and a southern independence
of conflict, in some areas mirroring Yemen’s pre-
movement remains active. Tribal networks and local actors
unification borders, remain static (Figure 1). Meanwhile,
are the most influential parties in many areas of the country.
Al Qaeda in the Arabian Peninsula (AQAP) and the
Islamic State have remained active in remote areas.
Figure 1. Yemen: Key Actors and Approximate Areas of Influence
As of July 2024
Source: CRS using ESRI and U.S. Department of State map data. Areas of Influence based on ACAPS data and U.N. and media reports.
Notes: STC – Southern Transitional Council. AQAP – Al Qaeda in the Arabian Peninsula. Al areas approximate and subject to change. Shading
includes lightly populated and uninhabited areas.
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Yemen: Conflict, Red Sea Attacks, and U.S. Policy
Conflict Status and U.S. Diplomacy
Guardian coalition patrolling the southern Red Sea. U.S.
Since 2015, conflict has caused widespread humanitarian
service personnel remain at risk from ongoing Houthi
suffering and significant infrastructure damage in Yemen,
attacks. The Houthis also have threatened to resume strikes
long the Arab world’s poorest country. In 2021, the United
on Saudi Arabia if it supports the U.S.-led coalition.
Nations estimated that 377,000 people had died as a result
U.S. military officials state that Iran is resupplying the
of the conflict (including combatants) and that nearly 60%
Houthis and providing targeting information and military
of deaths were from non-military causes, such as lack of
advice. According to the Defense Department, “Iran does
food, water, or health care. Foreign observers have
not control the Houthis” but without Iran’s assistance, “the
denounced human rights violations attributed to all parties.
Houthis would struggle to effectively track and strike
Since the truce expired in October 2022, fighting has not
vessels navigating shipping lanes through the Red Sea and
returned to “pre-truce levels.” Houthi cross-border attacks
Gulf of Aden.” Iranian support and Houthi experience may
into Saudi Arabia and Saudi-led coalition airstrikes largely
enable the group to pose enduring risks to maritime security
ceased. U.S. diplomats, led by Special Envoy for Yemen
in the region beyond any resolution of the current crisis.
Ambassador Timothy Lenderking, say they seek to
Humanitarian Situation
transform the truce into a durable ceasefire, enable a
According to the United Nations, 18.2 million people in
political solution, and support U.N. Special Representative
Yemen (more than half of Yemenis) need humanitarian
for Yemen Hans Grundberg. In June 2024, Grundberg
criticized parties to the conflict for having “
assistance, 4.5 million are internally displaced, and 17.6
reverted to a
million people are food insecure. Over 90% of food is
zero-sum game” and said “if the parties continue the current
imported, making the food supply particularly susceptible
escalatory trajectory the question is not if, but when, the
to international shocks. U.N. appeals remain underfunded.
parties revert to escalation on the battlefield.”
The U.N. Humanitarian Response Plan appeal for Yemen
Risks of renewed conflict in Yemen and widening U.S.-
sought $4.3 billion for 2023; by July 8, 2024, it was 40.7%
Houthi clashes are evident. In addition to the diplomatic
funded. The 2024 appeal seeks $2.7 billion; by July 8,
objectives described above, U.S. policy goals in Yemen
2024, it was 22.6% funded. Limits on movement and
include restoring security to shipping lanes, interdicting
bureaucracy constrain humanitarian access and affect aid
Iranian aid to the Houthis, combatting transnational terrorist
delivery, largely in Houthi-controlled areas, where the
groups, and ensuring humanitarian aid delivery.
Houthis periodically detain U.N. and aid workers.
Maritime Attacks and U.S. Responses
Counterterrorism
Following the October 7, 2023, Hamas-led attacks on
The State Department assesses that the “security vacuum”
Israel, and Israel’s military response in Gaza, the Houthis
in Yemen empowers Yemen-based terrorist groups, Iran’s
began targeting Israeli territory as well as commercial
Islamic Revolutionary Guard Corps-Qods Force, and
vessels transiting the Bab al Mandab Strait (see Figure 2).
Lebanon’s Hezbollah. U.N. sanctions monitors described
U.N. Security Council Resolution 2722 (2024) demands the
AQAP in January 2024 as “in decline” and facing
Houthis cease attacks, but attacks have continued and have
leadership losses, though senior U.S. counterterrorism
damaged several merchant vessels and injured and killed
officials have noted AQAP’s post-October 7 calls for
some merchant crew members. While the Houthis have
attacks on U.S. citizens and interests. The Biden
claimed to be targeting Israel-linked vessels, they have
Administration redesignated the Houthis as Specially
targeted vessels from many countries, diverting maritime
Designated Global Terrorists (SDGT) in February 2024.
traffic and driving up shipping global firms’ costs,
Yemen and the 118th Congress
insurance premiums, and ocean freight rates.
In the 118th Congress, the 2024 National Defense
Figure 2. Maritime Attacks and U.S. Responses
Authorization Act (P.L. 118-31) extends for one year an
existing ban on U.S. in-flight refueling of aircraft engaged
in hostilities in Yemen’s civil war. The act also requires
annual reporting to Congress on Iran’s support to the
Houthis. The House adopted H.R. 6046, which would direct
the Administration to redesignate the Houthis as a Foreign
Terrorist Organization (FTO). Some Members support U.S.
strikes on Houthi targets and new efforts to disrupt Iranian
support. Others have questioned the President’s authority to
order broad strikes and warn against possible unintended
consequences. Supplemental appropriations for FY2024
(P.L. 118-50) provided additional defense funds that may
support Yemen-related operations. In the coming year,
Congress may evaluate Administration efforts to weaken
Houthi capacity to threaten sea-lanes and interdict Iranian
support, while preserving longer term peace prospects and
Source: CRS, using data from U.S. Department of Defense and
avoiding deeper humanitarian crisis.
media reports. Attack and response data subject to change.
Christopher M. Blanchard, Specialist in Middle Eastern
U.S. forces have intercepted Houthi-launched projectiles,
Affairs
prevented attempted Houthi seizures of vessels, struck
Houthi targets in Yemen, and led the Operation Prosperity
IF12581
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Yemen: Conflict, Red Sea Attacks, and U.S. Policy
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