The Trump administration has indicated it plans to largely abdicate a U.S. role in Iraq's political future, despite the certainty that driving the Islamic State group from its remaining stronghold in Mosul – months, if not weeks, away – starts the clock on a dangerous new era for a country on the verge of fracturing along rival warring factions.

The prospect of a reduced U.S. role leaves a vacuum in crafting a long-term political solution to reassemble Iraq. Chief among the concerns is that the country's religious and ethnic populations – minority Sunni Muslims who felt victimized by the central government in Baghdad and now fear retribution, ethnic Kurds certain to seek independence for their semiautonomous region, and a majority Shiite population thought to be under the sway of Iran – will turn on each other without a common enemy to unite their efforts.

Ongoing instability also raises the possibility that another terror network could exploit Iraq's deep dysfunction, even as the fight against the Islamic State group, or ISIS, continues in Syria, where a civil war rages and where Russia is exerting influence that can be felt across the Middle East.

"It will require a tightrope walk the day ISIS is completely defeated in Mosul," says Nick Heras, the Bacevich Fellow at the Center for a New American Security and a regular adviser to the U.S. government about regional issues. "Right off the bat, from Day One, the U.S. is going to be in a referee-type role. The question is if the Trump administration wants to engage that role."

Despite assurances last week from Secretary of State Rex Tillerson to delegates from the 68 members of the coalition fighting the terror network, the White House is currently positioning itself to help support humanitarian and infrastructure needs in the immediate aftermath of the fighting and then withdraw from leading assistance to Baghdad and other centers of power.

"As a coalition, we are not in the business of nation-building or reconstruction," Tillerson told the delegates, who were assembled in Washington for a key summit discussing the future of the region. "We must ensure that our respective nations' precious and limited resources are devoted to preventing the resurgence of ISIS and equipping war-torn communities to take the lead in rebuilding their institutions and returning to stability."

Iraqi Prime Minister Haider al-Abadi emerged from a White House meeting with President Donald Trump this month apparently reassured by U.S. pledges of support in the war-fighting effort. However, the new administration's efforts in Iraq have centered almost exclusively on the military aspect, according to multiple advisers to Trump's national security team who spoke on the condition of anonymity, due largely to the president's preferences and that so many of the positions necessary for other issues, like diplomacy and international development, have not yet been filled.

But that leaves unsettled some complicated and crucial questions about Iraq's political alignment going forward. The Kurdish fighting unit known as the peshmerga enjoyed deep support from the U.S. and became one of the most effective military forces in this latest war, and the Kurds now seem all but certain to at least test international support for independence. They are supported by Turkey, which has deployed forces to northern Iraq to ensure their interests, too, in the aftermath of liberating Mosul.

By some estimates, the Kurds have increased the amount of territory they control within Iraq by as much as 40 percent, including the city of Kirkuk that accounts for some 40 percent of the country's oil production – land that Kurdish officials have hinted could be used as a bargaining chip to secure independence or that could wind up as a flashpoint for future conflict.

Meanwhile, the predominantly Shiite Muslim central government continues to work to convince the minority Sunnis that Baghdad and the federal security forces it controls are more trustworthy toward all of Iraq's interests than extremist, hard-line, propaganda-savvy alternatives like the Islamic State group. But distrust runs deep in Iraq, and Sunnis – some of whom found themselves aligned with the Islamic State group in their disillusionment with the central government – now brace for retribution.

Working toward a solution must begin quickly. U.S. military officials estimate victory in Mosul is months, if not weeks away, as this coalition of local fighting forces increasingly squeezes the terrorist group's remaining positions in the old part of the city, backed by intensifying American-led air power overhead.

The president's top decision-makers are split on how involved the U.S. should be in Iraq after wrapping up the aftermath of fighting the Islamic State group, according to the advisers to the Trump team. Those particularly who aren't career government or national security insiders, for whom Secretary of State Rex Tillerson has become the strongest voice, are indicating the U.S. has done enough for Iraq, and now it's time for someone else to take over.

Veterans like Defense Secretary Jim Mattis and Army Lt. Gen. H.R. McMaster, the national security adviser, believe the U.S. is in position to broker lasting stability in Iraq after the fighting stops and a responsibility to ensure the trillions of dollars the U.S. invested there over the last 13 years and 4,500 American lives lost aren't for nothing. The investment was long viewed as a bulwark against Iran's efforts to project its power more broadly across the region. With Tehran's influence heavy in Baghdad's affairs, its proxies fighting government forces to a stalemate in Yemen, and its ties to Russia deepening amid an increasingly successful campaign to preserve the leadership of Bashar Assad in Syria, that concern has never been more immediate.

The work to stabilize Iraq will be complex. Facing deep shortages of soldiers in 2014 after the Islamic State group's initial onslaught, the government in Baghdad empowered Shiite militias known as the Popular Mobilization Units or Popular Mobilization Forces, which continue to bear heavy responsibility for the war, albeit without direct U.S. support. They now have heavy weaponry and combat experience, and increasingly align themselves with Shiite politicians in Baghdad. As one local official remarked privately, Iraqis are used to militarizing society, but not to militarizing their politics.

In a brief meeting in February with Masoud Barzani, president of the Iraqi Kurdistan region, Vice President Mike Pence reiterated U.S. support for a unified, federal and democratic Iraq. But it remains unclear how much the U.S. is willing to commit to achieve that end.

Some officials who attended last week's summit, as well as observers familiar with the reconciliation process, were disappointed to learn that the White House isn't doing more to advance the political and diplomatic process that will follow the conflict.

The U.S. contributed 75 percent of the military power against the Islamic State group, Tillerson said, adding that its reconstruction contributions would be inverse – only 25 percent. His pledge comes amid a Trump administration move to sharply reduce funding for global assistance and the State Department.

"The United States will do its part," Tillerson concluded, "but the circumstances on the ground require more from all of you. I ask each country to examine how it can best support these vital stabilization efforts, especially in regard to contribution of military and financial resources."

State Department officials later clarified the U.S. plans to help provide "fundamental essentials" to displaced and newly liberated Iraqi citizens, such as water, electricity, and safe access to schools, but little more.

"Nation-building gets into long-term reconstruction, that sort of thing, which actually we haven't been very successful at," a senior department official said, speaking on the condition of anonymity.

The comments sent a clear message to at least some of the summit attendees: Prepare for the U.S. not to take a leadership role in Iraq's future. Many say it's the wrong message.

"There is a vast need in Iraq in political, diplomatic, economic and social terms that needs to be addressed, and you need to have a plan for that," says Sarhang Hamasaeed, a former deputy director of the Council of Ministers of the Kurdistan Regional Government of Iraq, now director of Middle East programs at the U.S. Institute of Peace.

"That plan is not there," Hamasaeed says. "The Iraqis will not come together on their own to come up with that plan. It's not a U.S. responsibility for that plan to exist, but it's in the U.S. national security interest for that plan to exist."

Those who have already overseen the removal of the Islamic State group from its strongholds outside Iraq confirm the aftermath presents a problem far more complicated than defeating those fighters.

Marine Gen. Thomas Waldhauser currently commands U.S. Africa Command and oversaw a U.S. air campaign in Libya that contributed to isolating and killing thousands of Islamic State group fighters holed up in the coastal city of Sirte, a bastion the terror network hoped to turn into a de facto lifeboat were it to lose its central presence in Iraq and Syria.

The city was considered liberated by January, though the U.S. has deployed additional strikes, including one in January, to attack Islamic State group positions in the country's south where they're trying to regroup.

"They're still there, ISIS is still in Libya," Waldhauser told a group of reporters on Monday. "Until there's a government in Libya that will be able to run the country and wield power there, they'll probably still remain there."

"It's a herculean effort to do that," Waldhauser said of recovering after Islamic State group control, "even under the best circumstances with a government that's in control."

And the Islamic State group will continue to exist in Iraq, even after Mosul is liberated. U.S. officials have already observed fighters from the terror network moving toward the Euphrates River valley, and particularly where it meets the Syrian border, a sprawling region logistically difficult for any military to target. The Iraqi air force struck a town across the border in February, making news for its coordination with Damascus and demonstrating a partnership that officials say will likely continue in the coming months, perhaps years.

Once Mosul is cleared and secured, attention will turn to "the other threats that exist," says Army Brig. Gen. William Turner with the U.S.-led coalition headquarters in Baghdad. "We are trying to anticipate how best to posture ourselves."

Turner oversees providing logistical support to all U.S. forces and some of the Iraqi military, as well as training local troops, police forces, emergency responders and counterterrorism units.