Immanuel Wallerstein has argued since 1980 that the United States peaked as a hegemonic power around 1970. He says the decline was slow at first but became precipitate during the presidency of George W. Bush. At first
the reaction to this argument, from all political camps, was to reject it as absurd. In the 1990s, quite to the contrary, it was widely believed, again on all sides of the political spectrum, that the United States had reached the height of unipolar dominance.
However, after the burst bubble of 2008, opinion of politicians, pundits, and the general public began to change. Today, a large percentage of people (albeit not everyone) accepts the reality of at least some relative decline of U.S. power, prestige, and influence. In the United States this is accepted quite reluctantly. Politicians and pundits rival each other in recommending how this decline can still be reversed. I believe it is irreversible.
Wallerstein points out that the recent kerfuffle over spying on friendly leaders would have been hushed up during the 1950s. Now it is to the advantage of leaders in their local politics to tweak the nose of the US. Not one of the strong actors in the Middle East takes their cue from the United States any longer.
Finally, there are two real consequences of which we can be fairly sure in the decade to come. The first is the end of the U.S. dollar as the currency of last resort. When this happens, the United States will have lost a major protection for its national budget and for the cost of its economic operations. The second is the decline, probably a serious decline, in the relative standard of living of U.S. citizens and residents. The political consequences of this latter development are hard to predict in detail but will not be insubstantial.