Whether or not you agree with the idea of America serving as an Empire (the evidence is strong, including territorial expansion, colonial development and the spread of influence via economics, culture, and religion), the question of collapse is a lot different. The historic vignettes of Imperial Collapse tell the same story over and over again: a society reaches the breaking point, and hovers on the edge, for decades or even centuries. Occasionally, this means moral issues, sometimes it involves health problems or climate change, but it almost invariably involves economics, including debt, over dependence on slave or low wage labor, import/export issues, and corruption.
Once a nation begins hovering on that brink, there is no turning back. The question isn't whether the society will collapse, but when. At this point, the single most common vignette occurs as follows:
The nation suffers unbearable problems. A great leader realizes the problems exist, gets into a position of power, and begins taking the reformative steps necessary to change the path of the nation. The populace is virtually unaffected, but the nobility suffers without the income from the graft and corruption, so they stir up the people in anger against the leader. Riots, wars, strikes, or simple assassination lead to the elimination of the great leader from power, usually by way of death. Once he is removed and things return to "normal," the people realize they have been fooled, and they react. Violently. From here things like cities being burned to the ground, noble estates being destroyed and neighboring kingdoms invading typically ensue, and the society suffers blow after blow far past the point of no return.
Can anyone else see the potential for this particular piece of the past to play itself out in the near future?