"This civilization is a world civilization. It can't fall like Egypt since there's no other things that could fall. "
Yeah, we live in a globalize community. the US ould easily fall from it's position as the single super-power. Influence in the UN (due to the US paying most of the UN's budget) would be lost, as China grows, the EU becomes more than just a trading block. Russia is in decline, falling population, poor health care, Ukraine is the same. I am sure the US could suffer a similar fate.
A turning point could be reached involving a huge change in public preception. (like the events of 9/11) however given the poverty of Mexico and the rest of south america, I can't see people emigrating from the US any time soon. (in the next two decades at least) In the far east of Russia (siberia) people say the optimists learn english, the realists learn Chinese.
I'm sure Chinese influence in siberia, loans to build hydro-electric dams in neighbouring central asian countries (the stans, tajik, uzbek, turkmen and Kyrgyz) is going to continue increasing, as is EU influence in things like the mediterranian Union, partnership agreements with Russia, eastern neighbours, continue Accession talks with Turkey...
meanwhile the US has huge interest in an oil based economy, OPEC countries support this, however given that peak oil discovery was reached in the 60-70s oil is going to un out sooner or later. (we're now able to pump a lot more oil which was too hard or too expensive to pump in the 60s so production hasn't dropped, but we're not finding that much more oil today) So unless the US can turn around and become the pioneer of a new 'green economy' or something equally radical and difficult to acheive. (like a 2,000 W society) eventually their position as a global leader will be eroded, and the rest of the world will move on without them.
This effectively amounts to a collapse of the USA's global hegemony, it took two world wars to bring about the end of the British Empire. Maybe Aghanistan will not result in a major military defeat, but if at home it become 'another vietnam' and so politically charged that the US never projects it's forces again it could be seen as a last stab from a dying superpower...