Alfred W. McCoy, author of the 1972 The Politics of Heroin in Southeast Asia, has written a very depressing, but probably quite accurate view of the near-future collapse of the American empire (Probably by 2020 or 2025). With two active wars, around 800 military bases arounthe globe, but a declining economy accelerated by the Republican/Blue Dog Democrat/Tea Party refusal to allow government stimulus measures to pull America's non-wealthy out of the sharp economic downturn that began in late 2007 with the collapse of the housing bubble (The wealthy are doing splendidly, thank you very much), America appears to be very solidly set upon a path to national decline and "imperial overstretch."
McCoy considers the invasion of Iraq to be the crucial event that future historians will compare to the Athenian attack on Sicily and the joint British-French-Israeli attack on the Suez Canal. These were the events that sounded the death knell for their respective empires. Of course, Athens and Britain continued long after their empires disintegrated, so naturally, the US wil survivie any approaching cataclysm. The anti-war left in the US considers the beginning of the Iraq War to be a good, universally-agreed-upon time to protest the Iraq War at least once a year. That date may one day be regarded as the beginning of the end of American supremacy over the rest of the world.
What's curious is to see all the yelling and screeching and beating of chests over the US budget deficit, with no thought of, perhaps, reducing America's military commitments. Very bizarrely, with states struggling to make ends meet and to keep citizens from falling into poverty and starving, the President and Republican opponents have agreed to extend tax cuts for millionaires and billionaires. Unfortunately, as with the political fight over the public option in the Affordable Care Act, it's pretty clear that the President isn't really on the progressive
side, despite his many earnest-seeming protestations.