Crash and burn.
Fareed Zakaria has an article in the May/June issue of Foreign Affairs titled "The Future of American Power: How American Can Survive the Rise of the Rest." Essentially, he argues that the United States will not collapse like previous powers, because America's problem is political stagnation, not economic incapacity. That's like arguing that because your car has a powerful motor, the lack of a steering wheel is not an issue. Just like a muscle car with no steering wheel, a powerful economy with an enfeebled political scene will make the crash more devastating, not less.