Afghanistan will be a key topic. President Obama made that known Tuesday night during his address from the Bagram Air Base in Kabul.
What's at stake during the NATO meetings at McCormick Place? Nothing short of Afghanistan's future.
Leaders of more than 50 NATO-aligned countries will be gathering here: presidents, prime ministers from countries ranging from Iceland to Korea, Mongolia to Tonga.
Each will land at O'Hare with his or her own political baggage and personal priorities when it comes to an Afghanistan exit strategy.
President Obama will host Afghan President Hamid Karzai, an uneasy ally in this process at best.Germany's chancellor Angela Merkel will be here. Her country is the third biggest contributor of forces. She has vowed to stay the course.
France is another matter. President Nicolas Sarkozy is facing a tough election this Sunday. His opponent, a socialist, says if elected he will begin pulling French troops out of Afghanistan as soon as he takes office.
Australia's prime minister Julia Gillard surprised many people last month when she announced she will begin pulling out Aussie soldiers this year and have them all home by next year, which, not coincidentally, is an election year.
And then there's America's longest and closest ally: Great Britain. Prime Minister David Cameron is on board with Obama's plan to have Afghans entirely responsible for their own security in 2014.
On Tuesday night, President Obama set the agenda for the NATO summit.
"In Chicago we will endorse a proposal to support a strong and sustainable long term Afghan force," he said.
Inside McCormick Place, leaders from more than 50 nations, supported by delegations of more than 7,000, will tackle tough topics in two days worth of meetings.
"This is way for the best alliance in the history of the world to get together and renew our vows," said Madeleine Albright, former U.S. Secretary of State.
Albright, in town as a co-chair of the NATO host committee, told ABC7's Kathy Brock progress at these summits can be tough to measure.
"It's one thing to contribute combat forces, it's quite another to contribute to the civilian component of this," she said. "There are other ways to help and contribute to this mission's success."
Beyond Afghanistan, issues on the table include Russia's opposition to a missile defense plan. Plus, NATO'S own future.
Twenty six of NATO's 28 member nations are from the European continent. Many of those countries are facing budget deficits that threaten their future. Citizens are in open revolt against austerity measures.
Rachel Bronson of the Chicago Council on Global Affairs said President Obama will have a tough time convincing others to pick up a bigger portion of NATO's bill.
"The big investor is the US," said Bronson. "Seventy five percent of the budget comes from the United States. That's gone up from 50 percent. That's a huge issue. The American people will not continue to support that."
Regarding NATO security, the FAA has advised that the airspace over Chicago will be limited to scheduled commercial and cargo flights. Private planes penetrating secured airspace, the FAA warned, may be shot down.
Coming up on ABC7 News at 6 p.m.: more of Kathy Brock's exclusive interview with Former Secretary Albright.