Operation Inherent Resolve will soon be resolved. On September 30, the final US troops are slated to withdraw from Iraq as the campaign to defeat the Islamic State of Iraq and al-Sham (ISIS) comes to an official end. The withdrawal closes a chapter of US military presence in Iraq that began with the 2003 invasion that toppled Saddam Hussein. It also raises several pressing questions. Below, we turned to our top experts on Iraq and the region for answers.
1. What is the significance of the end of Operation Inherent Resolve?
The end of the Defeat ISIS Coalition’s military mission and the departure of US troops from Iraq mark the conclusion of over two decades of US military engagement in Iraq. Since the 2003 invasion, the US military presence has been a defining feature of the US-Iraq relationship. The withdrawal in 2011 was followed by the return of US troops in 2014 after ISIS occupied nearly a third of Iraqi territory. Even as Operation Inherent Resolve (OIR) helped liberate Iraq from ISIS and included a degree of early cooperation with Iran-backed militias, the ongoing US troop presence became a target for militias and an irritant for Iraq’s Shia political leaders. The departure of US troops fulfills a core demand of Iraq’s militias and the Iraqi government. It also achieves a Trump administration priority to reduce US military engagement in the Middle East. The Iraq War is a prime example of the “forever wars” that President Donald Trump and a majority of Americans believe were mistakes. Even as Iraq has disappeared from the headlines, the legacy of the US military presence in Iraq has and will continue to shape American views on the Middle East and the use of US military force.
—Victoria J. Taylor is the director of the Iraq Initiative and Syria Project in the Atlantic Council’s Middle East programs. She served most recently as deputy assistant secretary for Iraq and Iran in the State Department’s Bureau of Near Eastern Affairs.
2. How does the US withdrawal impact Iraq’s efforts to disarm the country’s militias?
Even if the United States fully withdraws all its troops from Iraq on September 30, as stated in the two countries’ 2024 agreement, Prime Minister Ali al-Zaidi will still have significant challenges in meeting his own deadline of September 30 for bringing the Iran-backed Iraqi militias under the authority of the state. The hardest-line armed groups—Kata’ib Hizbollah, Harakat al-Nujaba, and Kata’ib Sayyid al-Shuhada—have so far given no indication that they are prepared to surrender their weapons to the state and integrate into Iraq’s armed forces. In fact, they have continued to carry out attacks. Moreover, despite the prime minister’s genuine efforts toward comprehensive security sector reform, little progress has been made in satisfying the demands of those factions that claim to be ready to work with the prime minister on a disarmament plan.
The real test for al-Zaidi will be whether he can convince the United States to stay the course in building a bilateral defense relationship and encouraging strong American investment while he buys more time to establish control over the militias that continue to resist disarmament. For the Trump administration, the test will be whether it can apply enough pressure on the Iraqi government, its Shia governing coalition, and the militias. Renewed attacks between the United States and Iran could derail the US withdrawal, especially if these factions, either on their own initiative or at Tehran’s direction, renew attacks on US personnel or Iraq’s neighbors. Under the current circumstances, the US should find the patience to stay. A departure of US troops from Iraq will be seen by many in Iraq and across the region as another example of the United States abandoning its partners.
—Alina L. Romanowski is a distinguished fellow with the Scowcroft Middle East Security Initiative at the Atlantic Council’s Middle East programs. She served as US ambassador to Iraq from 2022 to 2024.
3. How will Iran respond to the US withdrawal?
For the United States and its partners, OIR’s mission was never about Iran. But to Iran—even though ISIS was its most pressing security threat in 2014—OIR was another manifestation of a decades-long US threat to the Islamic Republic. A hypothetical US ground invasion would represent one of the greatest threats to the regime, and Iran’s security doctrine has prioritized reducing the US footprint in the region for nearly five decades. Seen against that history, OIR’s end could be considered a significant achievement for Iran.
However, in the context of the broader Iran war, it is mostly irrelevant. The mission’s conclusion will do little to shape the war or the evolving US role in the region. If anything, it removes one near-term option for Iran: of allowing Iraqi militias to fire at US troops during peacetime. Whereas September 30 was once a crucial marker for US-Iran policy, it now has little bearing on the relationship or the war itself.
—Nate Swanson is a resident senior fellow and director of the Iran Strategy Project at the Atlantic Council’s Scowcroft Middle East Security Initiative. He most recently served as director for Iran at the National Security Council.
4. Will the withdrawal lead to a resurgence of ISIS in Syria and Iraq?
The withdrawal of US forces and the end of OIR’s military mission does not necessarily mean we will see a resurgence of ISIS. OIR was always intended to be a temporary mission in Iraq, operating at the Iraqi government’s invitation since 2014 to help defeat ISIS. Since the group’s territorial defeat in Iraq in 2017, however, the threat has evolved. ISIS in Iraq now primarily relies on sleeper cells to intimidate local populations, exploit security gaps, and support its activities in Syria. The counter-ISIS mission in Iraq has also expanded to support the repatriation of more than 23,000 Iraqi citizens previously held in ISIS-affiliated detention sites in northeast Syria.
As the threat evolved, so too did the mission. OIR shifted toward “advising, assisting, and enabling” Iraqi partners by providing training, intelligence, and institutional knowledge as Iraq built its own counterterrorism capacity. The results have been significant. Earlier this year, the Defense Intelligence Agency assessed that ISIS in Iraq “almost certainly remains severely degraded, focused on its own survival, and unable to exploit instability arising from Operation Epic Fury.”
Yet Iraq now faces a complex security and economic environment, balancing competing expectations from Washington and Tehran while continuing to confront ISIS’s insurgency and manage thousands of ISIS-affiliated detainees. To ensure the counter-ISIS mission does not fall by the wayside, US-Iraqi bilateral relations need to remain focused on supporting Iraqi security forces, including through the US Military Group-Iraq; supporting Iraq’s efforts to manage ISIS-affiliated detainees; and sustaining programs for repatriated families leaving the Al-Amal reintegration facility after previously residing in Al-Hol camp. ISIS may no longer threaten Iraq’s survival, but continued US-Iraqi cooperation and vigilance are essential to preventing hard-won gains from eroding.
—Devorah Margolin is the Blumenstein-Rodan senior fellow at the Washington Institute for Near East Policy.
5. What does the withdrawal mean for Kurdish communities in Iraq and Syria?
The departure of US and coalition forces from Iraq could not come at a worse time. The broader Middle East is reeling from the continued conflict between the US and Iran, leaving local partners, including the Kurds, to pay a heavy price as they are continuously hammered by Tehran and its proxy networks. This regional volatility compounds an already brutal geopolitical reality for Kurds, which is the loss of their primary external shield. Years of de facto autonomy in Iraqi Kurdistan—and, until recently, northeast Syria—have been built largely in the shadow of Western military and security partnerships.
In Iraq, the countdown to the final coalition exit carries a set of acute dangers. The Kurdistan Regional Government finds itself squeezed between an assertive central government in Baghdad and hostile regional actors. As direct military assistance and institutional funding wind down, the Peshmerga lose a critical equalizer. Erbil’s leverage to negotiate a fair share of the national budget or protect disputed territories from encroachment is going to vanish amid a lack of political cohesion inside Iraqi Kurdistan. There may also be a psychological impact on the Kurdish population, for whom the US presence has often served as a kind of insurance policy.
Across the border in Syria, the withdrawal of American forces and the dissolution of local defense structures have forced Kurdish leadership into desperate, hurried integration deals with Damascus. Without US backing to deter the Syrian state, what’s left on the ground continues to be dismantled. Kurds who once managed their own security, schools, and local councils are now subjugated to the authority of a central government that has no sympathy to Kurdish identity.
Beyond high-level politics, what’s more troubling is the lack of protection for vulnerable ethnic and religious minorities such as Christians and Yezidis as both Iraq and Syria continue to provide ungoverned space for terrorists who could target them.
Thus, the withdrawal signals the end of an era in which foreign boots provided a buffer against central and regional predation. Left exposed, Kurdish people in both Iraq and Syria are discovering that survival now depends on painful compromises with the very central powers they spent decades trying to escape.
—Yerevan Saeed is a nonresident senior fellow with the Iraq Initiative in the Atlantic Council’s Middle East programs and the director of the Global Kurdish Initiative for Peace at American University.
6. How will US influence in Iraq change going forward?
The withdrawal changes the form of American influence rather than ending it. For over a decade, the US relationship with Baghdad ran mainly through a military channel: training, intelligence, air support, and the leverage that came with them. That finally changes on October 1. What replaces it is more typical of a relationship with the US—diplomacy, energy and infrastructure investment, arms sales, and financial ties, above all the Federal Reserve’s role in Iraq’s dollar access.
Two shifts stand out. First, influence becomes more transactional. Without troops, Washington’s main levers are economic: Iraq’s leadership has already signaled that US forces will leave while US companies stay. That gives Washington a stake in Iraq’s stability, but it also exposes Baghdad economically.
Second, the balance of outside power may shift. Iran’s networks inside Iraq’s security and political institutions do not depart on September 30. Baghdad has linked the pullout to bringing weapons under exclusive state control, though analysts doubt that goal will be met soon. If the militia question stalls, Iraq’s neighbors—and China, already the dominant buyer of Iraqi oil—may fill space that the US once occupied by default.
Counter-ISIS cooperation will continue but from a distance, with over-the-horizon intelligence and Jordan- and Gulf-based assets.
The net effect is a US role that is more conventional, more conditional, and easier for Iraqi politicians to defend at home, but with higher economic risks and more difficulty for Iraqi leaders to shape outcomes quickly when they turn.
—Safwan Al-Amin is a nonresident senior fellow with the Iraq Initiative in the Atlantic Council’s Middle East programs.
7. How does the withdrawal affect Syria’s security landscape?
The US withdrawal from Iraq creates both a challenge and an opportunity for Syria. For a decade, Iraq and Syria have effectively constituted a single theater in the campaign against ISIS. The US-Iraq agreement preserved the ability of coalition forces to support operations in Syria from Iraq through September 2026. As that architecture changes, Damascus will have to assume greater responsibility for preventing an ISIS resurgence.
That threat is not hypothetical. ISIS has explicitly declared a “new phase” of operations against the Syrian government, targeting its forces and seeking to exploit security gaps and communal tensions. President Ahmed al-Sharaa has been the target of ISIS assassination plots. A successful attack on Syria’s leadership, minorities, or state institutions could undermine the transition far beyond the immediate security consequences.
But the withdrawal also makes Syria a more important partner for Washington. Syria joined the Global Coalition to Defeat ISIS last year, and US and Syrian forces are cooperating against ISIS. With the American military footprint in Iraq shrinking, both sides have an interest in deepening intelligence sharing, counterterrorism cooperation, and the professionalization of Syrian forces. A more capable Syrian state would also reduce the space available to other armed networks, including Iranian-aligned groups, in the volatile corridor connecting Iraq, Syria, and Lebanon. A planned coalition meeting this fall gives Damascus an opportunity to articulate its needs, and Syrian officials need to become faster and more agile in identifying them.
The withdrawal should also serve as a warning. Syria cannot build its security strategy around an indefinite American military presence. This convergence of interests therefore offers a window: Washington should help build a Syrian partner capable of containing ISIS, while Damascus should use that partnership to develop capabilities it will eventually need to exercise with considerably less American support.
—Ibrahim Al-Assil is a nonresident senior fellow with the Syria Project at the Atlantic Council’s Middle East programs and a senior research fellow at Harvard Kennedy School’s Middle East Initiative, where he leads the Syria Transition Lab.
8. What are the implications of the withdrawal for US national security interests in the region?
With US troops departing Iraq at the end of this month, it is tempting to see the drawdown as evidence that the US-Iraq security relationship is winding down. That would be a mistake. Since the January 2020 strike that killed Islamic Revolutionary Guard Corps-Quds Force commander Qassem Soleimani and Popular Mobilization Forces leader Abu Mahdi al-Muhandis, Iraqi political pressure for a US withdrawal has remained strong. The continued US presence has also fueled a costly cycle in which Iran-backed militias attack American forces, the United States retaliates, and Baghdad is left managing the political fallout.
Ending that cycle may strengthen the relationship rather than weaken it. US forces are leaving in large part because Iraqi and American efforts succeeded in reducing the Islamic State threat. Iraqis understandably see that as a victory. Washington should too. A smaller US footprint also deprives Iran-backed militias of one of their most useful political arguments: that armed “resistance” is necessary to expel foreign forces. The question now becomes what Iraq and the United States can do together to better stabilize the region.
There is reason for cautious optimism. Baghdad is pursuing security-sector reform while signaling interest in deeper bilateral security and economic ties. The United States should seize that opening by preserving intelligence cooperation, counterterrorism support, and security assistance, while building stronger professional military relationships and expanding economic engagement.
A complete American disengagement would hand Iran precisely what it wants. A well-managed transition would do the opposite: reduce US exposure to militia attacks while preserving the relationships and capabilities that give Washington influence.
—C. Anthony Pfaff is a nonresident senior fellow in the Iraq Initiative. A retired Army colonel and foreign area officer for the Middle East and North Africa, Pfaff also served as director for Iraq on the National Security Council staff.
9. Why has Iraq faded from US public debate?
Iraq fatigue is nothing new. The United States has maintained a military presence in Iraq for twenty of the past twenty-three years, and the approaching departure of the last US military personnel will mark the second time Washington has withdrawn after a prolonged deployment.
The first, in 2011, came after eight difficult years that began with the 2003 invasion. The mismanagement and deadly insurgency that ensued contributed to a deeply complicated and traumatic relationship between the two countries.
As in 2011, the occupant of the White House has largely sought to distance himself from Iraq, portraying US involvement there as a mistake by previous administrations. But that is only part of the picture.
Attention, whether in policy circles or among the public, is also being pulled in many directions. A long list of international crises—from Russia and Ukraine to Venezuela, trade wars, and threats over Greenland—competes for public and political attention, not to mention domestic concerns. Even within the Middle East, Iran has become the central focus of US policy, leaving Iraq looking more like a secondary theater.
Still, even as US personnel leave, letting Iraq disappear from the conversation would be a mistake. As in 2011, developments in Iraq will continue to matter to US interests and the wider region. Iraq produces roughly 4 percent of the world’s oil. Its geography, which straddles ethno-sectarian fault lines, also gives it the potential to connect the Gulf, Turkey, and the Levant through new energy and trade routes. At the same time, it remains a home to pockets of extremism and a contested space for Iranian power projection and US and Arab efforts to contain it.
Turning Iraq into the kind of reliable partner Washington has long hoped for—on security, energy, business, and regional stability—may continue to be an elusive goal. But falling short of that aspiration is not a reason to walk away. If anything, sustained disengagement risks allowing Iraq to drift further into Iran’s orbit, opening the door to renewed instability and creating the very strategic headaches Washington has spent two decades trying to avoid.
—Omar Al-Nidawi is a nonresident senior fellow with the Iraq Initiative in the Atlantic Council’s Middle East programs and the director of programs at the Enabling Peace in Iraq Center.
10. What does the withdrawal signal about Washington’s appetite for military engagement in the Middle East?
Signed in the final year of the Biden administration, the agreement between the US and Iraq to phase out Operation Inherent Resolve reflected a mutual desire to conclude this international military intervention, allow increasingly capable Iraqi security forces to take the lead in containing the ISIS threat, and permit the establishment of a more durable bilateral security relationship.
The Trump administration and the new Iraqi government are finalizing implementation of the agreement. Paired with US forces also being drawn down in Northeast Syria, the move represents a bipartisan consensus that a US-led international role in the counter-ISIS fight should give way to the governments of Iraq and Syria (now in the post-Assad era). But that decision is complicated by two factors: 1) the risk that Syria’s national institutions, and its incomplete integration of Kurdish forces who were the United States’ key partners, and still developing Iraqi security capabilities will prove insufficient to prevent the reconstitution of the ISIS threat; and 2) the major deployment of US forces to the region in the current Iran war.
There remains a widespread American desire to end a major role in Middle East wars, and while the Iran war seems to cut against this notion, its unpopularity in the United States only reinforces the sentiment. This increases the importance of helping the governments of Syria and Iraq succeed, while also raising a concerning question: if Syrian and Iraqi capabilities prove insufficient to prevent the return of ISIS, will there be support in the United States for resuming its role in keeping this extremist organization at bay?
—Daniel B. Shapiro is a distinguished fellow at the Scowcroft Middle East Security Initiative in the Atlantic Council’s Middle East programs. He served as deputy assistant secretary of defense for the Middle East from 2024 to 2025.
Further reading
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Image: US Defense Secretary Pete Hegseth salutes as he stands next to Iraqi Prime Minister Ali al-Zaidi at the Pentagon, in Washington, D.C., on July 14, 2026. (Al Drago via Reuters Connect)