The End of Operation Inherent Resolve in Iraq: Questions and answers

The U.S.-Iraq partnership is entering a new era. In September, the international coalition to defeat the Islamic State of Iraq and the Levant (ISIL) is set to end its mission in Iraq.

The administration of former US President Joe Biden and the Iraqi government last year announced an agreed timeline for ending the Operation Inherent Resolve (OIR) mission in Iraq, which provides for continued coalition operations in neighboring Syria - where partners agree ISIS remains a serious threat - from Iraq.

This new phase in U.S.-Iraq relations presents many opportunities, challenges, and uncertainties. A group of specialists' responses to ten pressing questions about this moment of change-and reflection-cover Washington's position in the Middle East.

First: What does the end of Operation Inherent Resolve mean for the future of U.S.-Iraqi security cooperation?

Moving to a peacetime bilateral security cooperation framework, at Baghdad's request, would be an important test for both the United States and Iraq. The biggest risk is a repeat of Washington's neglect and Baghdad's misuse of security forces for political purposes after 2011, which paved the way for the rise of the Islamic State of Iraq and the Levant (ISIL). Another disadvantage of this transition is that the end of Operation Inherent Resolve will leave U.S.-Iraqi security relations at their lowest point since 2014, just as a new government will take power in Baghdad after elections scheduled for November. To avoid squandering the gains made from defeating ISIS and working to strengthen Iraq's fragile stability, Washington and Baghdad should commit to a sustained partnership in important areas such as intelligence sharing, procurement, training, and leadership development, rather than using the end of Operation Inherent Resolve as an excuse to sever security ties.

- Omar al-Nadawi is a Middle East political, security, and energy analyst and the current program director of the Center for Peace Empowerment in Iraq.

In the agreement announced by the United States and Iraq last year, the end of Operation Inherent Resolve included a commitment to transform security cooperation into a bilateral security partnership with Iraq. This shift allows for enhanced security and defense cooperation between the two countries in areas of mutual interest, such as counterterrorism, cybersecurity, border security, training, and information sharing. Through this more focused bilateral cooperation, the U.S. will have the opportunity to engage Iraq in some aspects of the broader CENTCOM strategy and enhance multilateral security cooperation with some of Iraq's neighbors to address regional threats, including continuing to fight ISIS. Strengthening the U.S.-Iraq security partnership will also contribute to improved cooperation and integration between Iraqi and Kurdish security forces. ISIS remains a regional and global threat, so building a long-term partnership with Iraqi and Kurdish security forces to enhance their role in the fight against ISIS should remain a key objective for the near future. Finally, strengthening the security partnership offers greater opportunity for engagement and intervention in Iraq's security sector reform process and in efforts to make the Iranian-backed Popular Mobilization Forces (PMF) more accountable to the state. As U.S. forces redeploy, the focus should not be on how many U.S. forces remain in Iraq or where they are deployed, but rather the future of this partnership should be based on what areas it will focus on and how bilateral security cooperation can be strengthened through the Iraq-U.S. Joint Supreme Military Commission and the annual formal security dialogue.

- Alina L. Romanovsky is a senior fellow at the Atlantic Council's Middle East Programs' Scowcroft Middle East Security Initiative. She served as U.S. Ambassador to Iraq (2022-2024) and Kuwait (2020-2022).

Second: How will the end of the coalition mission in Iraq affect U.S.-Iraqi relations?

The decision to end Operation Inherent Resolve is long overdue and should have been made eight years ago. The defeat of ISIS in 2017 achieved two goals: Removing the existential threat to Iraq's post-2000 transition to democracy and restructuring the Iraqi army into an effective security force capable of protecting the Iraqi people from a similar threat. Having achieved these two goals, there was no longer any justification for the survival of the security structure that had existed during the war. Hence, this operation sent the wrong message to Iraqis that U.S. forces will continue to remain in Iraq permanently.

The success of the negotiations and their implementation are positive steps. With the new BSA in place, Iraq and the United States can maintain an effective level of deterrence to counter any potential security threats, whether internal or external, to Iraq and the region. This paves the way for enhanced cooperation in various fields, in line with the spirit and substance of the U.S.-Iraq Strategic Agreement. The U.S. invasion of Iraq and its aftermath, as well as the nature of U.S. foreign policy toward Iraq and the Middle East, have made it difficult for the Iraqi people to buy into the idea of a fruitful partnership between the United States and Iraq. A full commitment to the implementation of this agreement will go a long way toward achieving this goal.

- Abbas Kazem is a senior researcher at the Atlantic Council's Iraq Initiative. He served as director of the Iraq Initiative in the Atlantic Council's Middle East Programs until July 2025. He also held a senior government affairs position at the Iraqi Embassy in Washington.

The end of the U.S.-led mission against the Islamic State of Iraq and the Levant (ISIL) is an important turning point in U.S. engagement in Iraq, providing an opportunity to reshape the U.S.-Iraqi security partnership, as well as the overall relationship with Iraq. For Iraq, the departure of U.S. forces from federal Iraq is a reaffirmation of Iraqi sovereignty after more than two decades of foreign troop presence. The U.S. military presence remains a point of political debate domestically, and normalizing this security partnership could reduce the source of friction. For the United States, it marks the end of the first "eternal war," a military intervention that ultimately cost billions of dollars and thousands of Iraqi and American lives. This relationship has remained firmly entrenched thanks to the continued U.S. military presence, even as Iraq continues to recede from the consciousness of the American public and, increasingly, from the consciousness of American policymakers. Although Iraq will remain important to advancing U.S. national security interests in the Middle East, this is also an opportune moment to create a more balanced partnership. U.S. engagement should focus on expanding bilateral relations by strengthening economic ties, including encouraging investment in Iraq's still untapped energy sector. Promoting Iraq's energy independence and prosperity will ultimately contribute to a more stable and secure Iraq.

-Victoria J. Taylor is the director of the Iraq Initiative at the Atlantic Council's Middle East Program. She most recently served as Deputy Assistant Secretary of State for Iraq and Iran in the State Department's Bureau of Near Eastern Affairs, where she advised senior State Department leaders on Iraq and Iran in the aftermath of the Gaza conflict.

The legacy of the U.S. military mission in Iraq

The legacy of the U.S. military mission in Iraq is one of profound contradictions. While it eliminated Saddam Hussein's dictatorship, laid the foundations for a new political order, and enabled the defeat of the Islamic State of Iraq and the Levant (ISIL), it also caused continued instability, sectarian fragmentation, and a dramatic change in regional power dynamics. For Iraqis, the consequences varied sharply. For many Sunnis, the fall of Saddam Hussein was a collapse of their historical political dominance, leading to their marginalization, exposure to violence, and the emergence of an insurgency. For the Kurds, it was more of a liberation story: The U.S. mission enabled the consolidation of the Kurdistan Regional Government, promoting relative security, political independence and economic growth. For the Shia majority, the initial optimism, rooted in new political representation, was gradually replaced by disillusionment as governance faltered, corruption spread and sectarian violence worsened. From a geopolitical perspective, the U.S. mission produced results that are often characterized as counterproductive. The overthrow of the former Iraqi dictator paved the way for Tehran to expand its influence through political, economic and paramilitary channels throughout Iraq and the wider Middle East.

The human cost of the intervention was enormous: hundreds of thousands of Iraqi civilians were killed, millions were displaced, and the country's infrastructure was catastrophically damaged. Beyond the physical destruction, the war has destabilized social cohesion, eroded trust in state institutions, and created a generation scarred by the effects of conflict. For many observers, these humanitarian and developmental consequences represent the most enduring and tragic dimensions of the U.S. mission. This ending is widely seen as a strategic setback for the interests of the United States and its regional allies, as it altered the regional balance of power in ways that strengthened Iran's position while straining Washington's alliances. Analysts often point to Iraq as a cautionary tale of "geostrategic overreach," where short-term military success undermined long-term strategic stability.

Yerevan Saeed is a non-resident fellow at the Iraq Initiative in the Middle East Programs of the Atlantic Council. Said is a Barzani Scholar-in-Residence in the Department of Politics, Governance, and Economics at American University's School of International Service, where he is also the director of the Kurdish Global Peace Initiative.

The second U.S. military mission in Iraq, launched in 2014, played a crucial role in liberating Iraq from ISIS and contributing to its defeat in Syria. Without U.S. intervention, and due to the weak capabilities of Iraqi forces at the time, the war could have dragged on for years, with the potential for escalating and spreading sectarian violence. While the military achievements of this mission are undeniable, it also shows the dangers of alliances forged under pressure, as they may sow the seeds of future conflicts. Remarkably, factions that relied heavily on US support to fight ISIS are now celebrating Washington's exit from Iraq as a victory over the "occupation." But with the withdrawal of US forces from Iraq, what these groups see as a victory may enable Israel and the US to target them, and Iraq in general, in any future confrontation with Iran.

Omar Al-Nadawi

The legacy of the U.S. mission in Iraq is complex and full of differing perspectives among Americans and Iraqis alike. Bottom line, for the sake of our strategic interests, the United States has stood by Iraqis more than any other nation and has worked to stabilize Iraq on numerous occasions. We share the tragic loss of life, the difficulties in defeating the Islamic State of Iraq and the Levant (ISIL), and the challenges in establishing good governance, the rule of law, and effective institutions after the fall of Saddam Hussein. Not all Iraqis share a positive view of the United States, but the majority recognize that a strong U.S.-Iraqi partnership, not just in security areas, is critical to Iraq's future development and sovereignty and the stability of the region.

-Alina L. Romanovsky

IV: Withdrawal or Transformation?

Whether this is a withdrawal or a transition will depend on the details. The administration of U.S. President Donald Trump has yet to announce how the presence of U.S. forces will change, including whether, how many, and where they will be stationed in federal Iraq. The answers to these questions directly affect the future of U.S.-Iraq security cooperation and whether the U.S. will remain a strategic military partner for the Iraqi security forces. Even with fewer U.S. forces, the United States can manage an effective transition from the global coalition to defeat ISIS to a bilateral military relationship that maintains core operational capabilities for counterterrorism cooperation. However, a more comprehensive withdrawal of U.S. forces and a more limited program of security cooperation would significantly reduce U.S. influence in Iraq and provide an opportunity for Iran to exploit.

-Victoria J. Taylor

V: How will ending the Operation Inherent Resolve mission affect U.S. security interests regarding Iran and counter-extremism?

While the U.S. role in Operation Inherent Resolve has been crucial in the fight against ISIS, it has antagonized Iran, which would prefer not to have any U.S. presence in Iraq or anywhere else in the Middle East. So we find ourselves in an awkward position. ISIS and Iran are still a threat, albeit a weakened one. While ISIS's military capabilities in Iraq have diminished, its global presence will make it difficult to eradicate. If the next Iraqi government adopts policies that exclude Sunnis from political participation, the conditions that paved the way for the return of ISIS in 2014 will be repeated. It is in our interest to build a close relationship with Baghdad to promote more inclusive policies and strengthen cooperation to monitor and limit ISIS's influence.

For Iran, the Israeli and American strikes have made it a less attractive partner, which has contributed to the reluctance of its factions in Iraq to clash with Israel, despite its hostile rhetoric. At the same time, this has increased Tehran's determination to limit U.S.-Iraqi relations and the U.S. military presence. Therefore, any improvement in relations can be expected to be met with a reaction from Iran aimed at restricting the U.S. presence and preventing the expansion of economic and other ties, which are the foundation of Iraq's stability. Ultimately, it is in Iraq's interest to maintain relations with both the United States and Iran. This requires a delicate balancing act, and is unlikely to satisfy either side. But I believe Iraq's interests are consistent: Fighting terrorism, avoiding regional conflicts, and supporting stability in the region.

- Anthony Paff is a visiting scholar on the Iraq Initiative at the Atlas Center for Strategic Studies and a research professor of military ethics at the Strategic Studies Institute at the U.S. National Defense University in Carlisle, Pennsylvania.

Much will depend on whether the United States and the next Iraqi government treat the post-Operation Inherent Resolve relationship with the seriousness it requires. If, as expected, the November elections result in a government more dominated by the Coordination Framework factions-with moderates like Haider al-Abadi absent-then relations are likely to be tenuous at best. In this case, the loss of the U.S. "eye and ear" in Iraq will create a more permissive environment for Iran to expand its influence and rebuild its regional power, compensating for the setbacks suffered by Hezbollah and the overthrow of the Bashar al-Assad regime in Syria. Such moves would increase the risk of Iraq being drawn into the next regional conflict, with major implications for Middle East stability, global energy security, and the threat of terrorism.

-Omar Al-Nadawi

VI: How will the end of the Operation Inherent Resolve mission affect U.S. security interests in Syria?

Terminating the Operation Inherent Resolve (OIR) mission would significantly weaken U.S. security interests in Syria. Operation Inherent Resolve has been the backbone of the intelligence sharing and coordinated strikes that have kept the Islamic State of Iraq and the Levant (ISIL) under control. If the mission ends without a replacement framework, ISIS cells in the Badia and along the porous border could reemerge, threatening regional stability and U.S. partners.

Strategically, losing Erbil as a platform for Syrian operations after 2026 would force a move to Kuwait, reducing proximity, flexibility, and credibility. The legal basis for U.S. operations, currently tied to Iraq's 2014 letter to the UN, is also fragile-if Baghdad revoked it, Washington would lack a clear international mandate. Syria's request to join the Global Coalition to Defeat ISIS could provide a new legal basis, preserve the coalition's existence, and even expand European participation.

Beyond counterterrorism, ending international coalition operations against ISIS would erode U.S. leverage vis-à-vis Russia and Iran within Syria. For the United States, maintaining a credible counter-ISIS mission is not just about defeating ISIS, but about maintaining influence, ensuring the security of allies, and preventing a vacuum that adversaries could exploit to undermine regional stability and Syria's fragile transition.

-Ibrahim al-Assil is the director of the Syria Project at the Atlantic Council's Middle East Programs. He is also a postdoctoral scholar at Harvard University's Middle East Initiative at the Belfer Center.

The end of the Operation Inherent Resolve (OIR) mission in Iraq comes against the backdrop of the political transition in Syria, with instability in Syria potentially creating an opportunity for the return of the Islamic State of Iraq and the Levant (ISIL). The U.S. military presence in Iraq remains the primary logistical platform, not only for ISIS operations in Iraq but also in Syria. While a reduced U.S. military presence in federal Iraq is likely to weaken counter-ISIS capabilities there, the September 2026 deadline for ending the logistics platform in Iraq for Operation Inherent Resolve operations in Syria will pose a greater security challenge if the U.S. chooses to continue its military presence in Syria. More generally, the U.S. security partnership with Iraq continues to serve as a counterweight to Iranian influence in Iraq. The size and scope of the future U.S. security relationship with Iraq is also of concern to other regional partners who want to see a stable Iraq, with the Gulf states, Jordan, and Israel watching the next steps closely.

-Victoria J. Taylor

The continuation of Operation Inherent Resolve (OIR) in Iraq to support counter-ISIS operations in Syria through the end of 2026 will provide a key area of bilateral security cooperation between the United States and Iraq, and engage in regional dialog about the trajectory of the new Syrian government. What happens in Syria could affect the stability of Iraq and the region. The Iraqi prime minister and his security forces are concerned about the security situation in Syria, including the movement of non-state actors, terrorists, and drug trafficking across the Syrian-Iraqi border. As Operation Inherent Resolve comes to an end, security issues across that border and in Syria will provide another vital area for enhanced bilateral cooperation.

-Alina L. Romanowski

Seventh: How can the United States ensure that the end of Operation Inherent Resolve does not lead to a decline in U.S. influence?

The United States will need to remain closely engaged in building a security partnership that supports U.S. interests in the region and shapes Iraqi decision-making. While Washington and Baghdad would like to see increased economic investment in Iraq, many issues remain contentious, including the institutionalization of the Iranian-backed Popular Mobilization Forces, corruption, oil smuggling, Iranian influence, non-state armed actors, and terrorist groups that undermine Iraq's sovereignty. These and other issues will complicate continued U.S. military cooperation. Without a U.S. security partnership, the prospects for additional U.S. economic investment in Iraq will be greatly diminished. The recent visit of the new CENTCOM commander, Vice Admiral Brad Cooper, shortly after taking up his new post, sends a signal to Iraqi Prime Minister Mohammed Shi'a al-Sudani and his military leadership - as well as to the region - that an active U.S.-Iraqi security partnership remains important to the United States. Now, it's up to the Iraqis to make it happen.

-Alina L. Romanowski

Eighth: How have Sunni attitudes toward the U.S. military presence changed and how does the Sunni community view the departure of U.S. forces?

Sunni Arab attitudes toward the United States began to change positively long before Operation Inherent Resolve (OIR)-during the "surge" and "awakening" phases of the mission, when many realized that cooperation with the United States was the best way to defeat al-Qaeda in Iraq and limit the influence of Shia militants in Baghdad. This pragmatic outlook continued through the war against the Islamic State of Iraq and the Levant (ISIL). Today, with the defeat of ISIS and the increasingly reciprocal nature of Iraqi politics, Sunni leaders may feel less dependent on the United States as a protective buffer. However, Sunni communities remain vulnerable: Whether the threat is the return of ISIS from Syria, a regional war, or renewed sectarian conflict, these communities often bear heavy costs when Iraq enters another crisis.

Omar Al-Nadawi

IX: How does the Shia political elite view the end of the Operation Inherent Resolve mission and the future of the U.S.-Iraqi partnership?

Iraqi Shia leaders view this moment with mixed feelings. On the one hand, the end of the Operation Inherent Resolve mission serves their pro-Iranian leanings and interests. Tehran is increasingly becoming the Shia leaders' primary strategic partner and protector, and guarantor of their ultimate goal of staying in power. Iran already has clear achievements in helping these leaders maintain this influence - during the post-2021 election race, Tehran helped Shia leaders defeat the Sadrist challenge. On the other hand, they are worried about losing the United States because of their dependence on Iran. It is very difficult for them to find a comfortable balance between Washington and Tehran, especially given the shrinking room for maneuver they face as a result of the current confrontation between the United States and Iran.

-Aqeel Abbas is an academic and journalist based in Washington, DC. His research and publications deal with national and religious identities, as well as modernity and democracy in the Middle East.

X: What impact will the end of Operation Inherent Resolve have on Kurdish interests, and how will this contribute to reshaping the dynamics between Erbil and Baghdad?

The first real test of Iraq's federal structure and acceptance of the Kurdistan Region as a federal autonomous region will come after September 2026, with the end of the Operation Inherent Resolve mission. If Washington opts for a full withdrawal after 2026, Kurdish interests will undoubtedly face significant setbacks. For Iraq's Kurds, the U.S. military presence has been a security umbrella against Baghdad and a strategic guarantor of Kurdish autonomy. The absence of U.S. forces would shift the balance of power decisively in Baghdad's favor, weakening Kurdish influence. Historically, this imbalance has had destabilizing consequences. The 2011 U.S. withdrawal created a political vacuum, as the Shia-led government marginalized Sunni politicians, fueling grievances that culminated with the rise of the Islamic State of Iraq and the Levant (ISIL). Kurdish leaders fear a similar trajectory today, as Baghdad may take tougher measures to curtail Kurdish autonomy and consolidate central authority.

The departure of Operation Inherent Resolve will reshape the dynamics of relations between Erbil and Baghdad by removing a key external stabilizing factor. For the Kurds, U.S. forces were not just a military presence; they were a pillar of security, stability, and influence. Whether the post-Operation Inherent Resolve era reverses the instability that followed 2011 or opens the door to a more pragmatic Baghdad will depend on the central government's willingness to avoid repeating the mistakes of the past. Will Baghdad return to authoritarian centralization that could exacerbate ethnic and sectarian divisions? Or will it make constitutional compromises and recognize that lasting stability requires respect for constitutional frameworks? The stakes extend far beyond Kurdish autonomy: The outcome will affect Iraq's internal cohesion and the broader balance of power in the Middle East.

- Yerevan Saeed