More than 50 world leaders were gathering in Chicago for one of the biggest NATO summits in history Sunday aiming to draw up a unified exit strategy in Afghanistan after a decade of war. A huge security operation has swung into place in the hometown of US President Barack Obama, with police deployed along the main arteries, some on horseback, as Coast Guard boats topped with machine guns patrol the river. It is the first summit of the 28-member North Atlantic Treaty Organization on US soil in more than a decade, and follows a two-day summit of G8 leaders hosted by Obama in the seclusion of Camp David, Maryland. In a sign of the heightened tensions, authorities in the Windy City, already bracing for massive protests, Saturday charged three men with plotting to attack Obama's campaign headquarters and other targets during the summit. Despite a myriad of issues facing the 63-year-old organization founded in the wake of World War II as it confronts shifting 21st century realities, the Chicago summit is set to be dominated by Afghanistan. Among the world leaders at the table will be Afghan President Hamid Karzai, who has headed up his country since the US ousted the hardline Taliban Islamic leadership in late 2001. Despite the stubborn Taliban insurgency, war-weary international forces are seeking to hand control of security to Afghan forces while withdrawing some 130,000 foreign combat troops by the end of 2014. Karzai comes armed with a firm demand for $4.1 billion a year to fund his security forces after the pullout -- fearing his country could descend into a new civil war. The United States is expected to foot half the bill while hoping the international community will stump up the rest. But analysts have warned NATO's rush to extricate itself from the Afghan quagmire carries high risks to stability. "The idea that the official transition timeline can generate even minimally conducive conditions on the Afghan ground -- that would substantiate claims that the transition strategy can succeed -- is a delusion," wrote Barbara Stapleton, former deputy to the EU special representative for Afghanistan. Going ahead regardless, "increases the risk of the Afghan state's collapse and with it, the prospect of strategic failure for NATO," she said in a report for the independent Afghanistan Analysts Network. Also key to success in Afghanistan is the cooperation of Pakistan. "We can't solve the problems in Afghanistan without the positive engagement of Pakistan," NATO Secretary General Anders Fogh Rasmussen said Saturday. But planned talks between Rasmussen and Pakistani President Asif Ali Zardari floundered at the last-minute Saturday, officially canceled after Zardari's plane was delayed. France's new President Francois Hollande has meanwhile shaken up the carefully crafted transition plan, vowing to bring his 3,500 combat troops home in 2012, a year earlier than planned. French Defense Minister Jean-Yves Le Drian said Saturday however that France's plans would not affect NATO "unity." "The unity of the alliance and the solidarity of the allies will be reiterated. This will be, in my opinion, a summit of consensus," he told AFP after meeting his US counterpart Leon Panetta. "Let me be clear, NATO will continue to stand shoulder to shoulder with Afghanistan," Rasmussen said Saturday. But Hollande is not the first leader to push for an early withdrawal. Canada and the Netherlands have already switched to training missions while Australian Prime Minister Julia Gillard indicated her troops could leave next year, although her government later said they would stay through 2014. Obama and his fellow leaders will take other key decisions, activating the first part of a missile shield for Europe and announcing a slew of military cooperation projects to cope with mounting austerity. Governments are feeling the pinch as Europe's debt crisis forces budget cuts across the board. The United States, which accounts for 75 percent of NATO military spending, has pressed Europeans to pull their own weight. To cope with the austerity, NATO will announce more than 20 joint projects to pool military hardware as part of a so-called "Smart Defense" initiative. NATO has touted a planned US-led missile shield for Europe as a shining example of military cooperation. A first step to the shield will be the announcement at the summit of an "interim capability" putting US warships armed with missile interceptors in the Mediterranean, and a radar system based in Turkey under NATO command.