Neither a sweltering Sunday in Chicago nor thousands of angry protesters could stop the momentum for NATO heads of state who gathered in the Midwest to agree on a roadmap toward ending war in Afghanistan.

Anti-NATO hackers took down the city's home page for hours May 20 just as leaders of the military alliance opened two days of scheduled meetings in Chicago and as protesters took to the streets. Despite a crushing wall of demonstrators along Michigan Avenue, Chicago police reported less than 100 arrests overall, several dozen injuries, and no deaths, even though one police officer was stabbed in the leg during street confrontations.

Chicago mayor Rahm Emanuel-the former White House chief of staff and a key backer of President Barack Obama-raised $55 million to pay local authorities overtime and host the summit in the president's hometown, the first ever in the United States outside Washington, D.C.

The two-day event climaxed May 21 when the 28 heads of state who make up the Atlantic military alliance formally agreed to a framework for winding down the combat mission in Afghanistan by the end of 2014. Under that agreement, NATO allies will turn over the lead responsibility for providing security to Afghan forces next year, bringing to an end the foreign involvement in the decade-long war that began with a U.S. invasion shortly after the attacks of 9/11.

"We leave Chicago with a clear road map," President Obama said. "This alliance is committed to bring the war in Afghanistan to a responsible end."

But the show of unity did not hide serious challenges-and disagreements within the U.S. command structure-for NATO in bringing to a close its longest war.

In his speech to the summit on May 21, Obama emphasized the day soon when "the Afghan war as we know it is over." But the NATO commander in Afghanistan, U.S. Marine Gen. John Allen, sounded a more cautious pace: Noting "there is a narrative out there" that combat operations will end in 2013, Allen said U.S. forces will be fighting right up until NATO formally ends its combat mission in December 2014.

Obama himself, in a speech delivered during a surprise visit to Afghanistan in May, said that the United States would withdraw more than 20,000 troops by the end of this summer, with all combat operations led by the United States to end by 2013. The difference in the two messages, observers in Chicago noted, may reflect 2012 circumstances: One commander is running for reelection while the other is running a war.

Allen also said that the Taliban remains far from defeated: "Combat operations will continue in the country [until] December 31, 2014. ... I don't want to, again, understate the challenge that we have ahead of us. The Taliban [are] still a resilient and capable opponent."

Meeting with reporters by telephone the day after the summit concluded, U.S. permanent representative to NATO Ivo Daalder emphasized a fast track for turning military operations over to Afghan forces. While the Afghan National Army is taking the lead in 50 percent of all combat operations currently, he said, by the end of this summer it will lead in 75 percent of all combat operations.

Unlike Obama, who has said little about a continuing force after combat operations end, Daalder said he was "confident we will be able to sustain in Afghanistan a NATO force in 2015 and beyond." But he admitted when questioned by reporters that adequate funding for defense will be a major factor in how robust and effective a long-term force to prevent the return of al-Qaeda and the Taliban will be: Continued defense cuts by the United States and European nations will "bite into" operations down the line, he said.

Currently the United States pays more than 10 times any other member nation in sustaining NATO operations. And while the EU is locked in its own fiscal crisis, Congress and the White House are debating a defense reauthorization bill-with Obama pledged to cut $487 billion from Pentagon spending over the next decade.

Key to the Obama administration's strategy to reduce defense spending while fighting terrorist threats: the increased use of drones. Coming off a 30-minute closed door meeting in Chicago with Obama, Turkish president Abdullah Gul said only Congress was blocking the sale of armed Predator drones to Turkey. The Obama administration supports selling the unmanned aerial vehicles to Turkey to aid its fight against Kurdish rebels. But Congress is likely to resist: The drones pose a potential threat to the legitimate Kurdish regional government-a key U.S. ally-in northern Iraq (fronting the Turkish border), and to Israel, whose relationship with Turkey has grown increasingly strained as Gul has moved his country away from a secular government toward more conservative Islamic rule.