Fact Sheet | August 12, 2025
The UK and U.S. joint counterterrorism strategy against ISIS remains a pivotal element of international security policy amid evolving Middle Eastern dynamics. Despite ISIS’s territorial losses, the group continues to pose a significant threat through insurgent attacks, ideological influence, and global networks. This strategy is crucial now to address resurgent ISIS factions, foreign terrorist fighters, and the protection of Western interests. The core challenge is sustaining cooperation to degrade ISIS capabilities while mitigating regional instability and counter-radicalization.
Security and Military Cooperation
- The UK is a leading member of the Global Coalition, alongside the U.S. and 81 other partners committed since 2014 to degrade and defeat ISIS.
- The UK deploys over 1,000 military personnel in the region, including RAF air strikes in Iraq and Syria, training Iraqi security forces, and intelligence-sharing with coalition partners.
- Since inception, the coalition has liberated approximately 7.7 million people from ISIS’s rule.
- The Royal Air Force has executed over 4,300 precision strikes against ISIS targets.
- The U.S. maintains extensive ground operations and intelligence operations in Iraq and Syria, coordinating with local forces.
Legislative and Strategic Frameworks
- The UK’s CONTEST counter-terrorism strategy (2023 update) emphasizes disrupting terror threats preemptively using all state powers, including multi-agency cooperation and legislative reinforcement for earlier interventions.
- The National Security Strategy 2025 commits the UK to a generational 5% GDP defense and security spending increase. This underpins stronger NATO leadership and sovereign technological capabilities.
- The Terrorism (Protection of Premises) Act 2025 (Martyn’s Law) aims to enhance public safety against terrorist threats domestically.
- The U.S. Congress has authorized continued counter-ISIS military and intelligence operations under relevant defense spending and counterterrorism provisions.
Background and Historical Political Context
ISIS (Islamic State of Iraq and Syria), also known as Daesh, rapidly expanded in 2014, controlling significant territory across Iraq and Syria, proclaiming a caliphate. The UK and U.S., alongside the Global Coalition, launched extensive military campaigns to reverse these gains, combining air power, intelligence sharing, training local forces, and cutting terrorism financing. Key milestones include the extension of RAF airstrikes to Syria after the Paris attacks in 2015 and strengthened bilateral intelligence cooperation.
These efforts evolved politically with periodic updates to national counterterrorism strategies (UK’s CONTEST and the U.S. Counterterrorism policies), reflecting new priorities such as addressing extremist narratives online and returning foreign fighters. Diplomatic cooperation also expanded to tackling ISIS’s financing and regional stabilization.
Main Actors and Strategic Stakeholders
UK Government: Led by the Ministry of Defence, Home Office, Foreign Commonwealth & Development Office, focusing on military action, intelligence, and community counter-extremism. The Conservative government emphasizes NATO cooperation and defense investment.
U.S. Government: The Department of Defense, State Department, and intelligence agencies drive U.S. military and diplomatic efforts. Bipartisan support persists for counter-ISIS operations, though domestic debate continues on troop presence.
Global Coalition Members: 83 countries working multilaterally to combat ISIS’s global terror network.
Local Forces: Iraqi Security Forces and Kurdish Peshmerga are key beneficiaries of UK and U.S. training and support.
ISIS and Affiliates: Adapted insurgent groups continuing guerrilla warfare, global attacks, and online radicalization campaigns.
Political Parties and Interest Groups: Across both countries, parties broadly support counterterrorism but debate exists around civil liberties, immigration policies related to returning fighters, and defense spending.
Current Developments and Policy Measures
The UK’s National Security Strategy 2025 frames new investments to counterterrorism and border security, emphasizing modern technology and intelligence cooperation. The U.S. continues counter-ISIS operations with a focus on preventing resurgence and disrupting financing networks. Recent political rhetoric in both countries stresses the importance of sustaining the Global Coalition leadership.Concerted efforts focus on tackling online extremist content via legislation such as the UK’s Online Safety Act 2023. Enhanced joint intelligence initiatives, including Five Eyes collaboration, underpin the early identification of threats. The UK’s Counter Terrorism Policing has expanded community engagement to disrupt radicalization domestically.
Challenges and Risks in the Counterterrorism Strategy
- Political Risks: Balancing civil liberties with enhanced surveillance and intervention powers sparks domestic debates about privacy and human rights.
- Security Risks: ISIS remnants remain capable of insurgent attacks and inspiring lone-wolf terrorism globally. Foreign terrorist fighters returning home pose ongoing threats.
- Economic Risks: Sustained defense spending increases place financial burdens on national budgets, potentially affecting public approval.
- Unintended Consequences: Military actions may exacerbate local instability or cause civilian casualties, fueling further radicalization.
- Regional Instability: Fragmented Middle East politics complicate coalition efforts and risk geopolitical rivalries undermining counterterrorism unity.
Implications for Domestic and International Politics
The joint UK-U.S. counterterrorism strategy deeply influences domestic and international policymaking. Domestically, it shapes security legislation, civil-military relations, and immigration controls. It affects voter sentiment on national security, with heightened public concern over terrorism influencing election campaigns and party platforms.
Internationally, this cooperation reinforces NATO and Global Coalition unity and signals a commitment to combating transnational threats. It shapes diplomatic relations with Middle Eastern states, balancing counterterrorism with broader geopolitical interests. The success or perceived failures of this strategy could shift alliances and affect future international security frameworks.
