Personally, I think most Americans are in a state of severe denial. Like most states of denial, this one is due to Americans not being strong or courageous enough to face the facts. Sadly, it's going to take more than a Pew Survey to get Americans to begin to deal realistically with our country's -- and the world's -- problems.
In response to another question, their views towards Americans (in contrast to the U.S.) are generally in the range of 65% favorable, which should help repair a lot of the damage to the country's image if a new administration appears more willing to actually engage the global community.
What I found somewhat remarkable was that Americans very much realized the extent to which their nation is disliked by the rest of the world: only 26% believe that the U.S. is generally liked, while 69% say that it is disliked. This is probably a healthy skepticism. (Canadians have the most positive view of their perception by the rest of the world, with 94% thinking that they're liked. The only other countries surveyed which feel that the world doesn't like them are Russia and Turkey.)