The decline of any nation historically starts with people not willing to sacrifice for it. In this case a moral rightousness prevents action in it's best interest. No worry though, there are several other nations that will sacrifice and become number one through action and devotion while we verbally claim moral high ground all the way to the end.
Now about those lives...
Do you think our sanctions do not kill? Do you think keeping other nations economically down does not kill? You are drawing a mighty fine line.
Do they kill Americans? No, the other guys dies. Tough shit. If we are pursuing a just policy, well then, the death will stop if they play ball with justice. That is the whole point. In fact, you really advocate a devolution, a return the brutal world we have been continually evolving away from as a nation, in fact that is what makes America what it is. The entire idealogical struggle in this country has been against us as a society being subsummed into the European and Asiatic Ideals that we are just cogs in a machine that serve a greater society, and becoming the kind of fucking animals they became in the process of pursuing imperialism. The idea that the needs of society as a whole far outweigh that as an individual is the very idea the founders of this country fought against. That is the real reason they failed as societies, imperialism is an incredibly stupid idea. All imperialist nations have met disaster.
The US Constitution is the embodiment of the idea that while society's needs must be recognized, it is the individual who is paramount - his rights are paramount and his power over the state is ultimately well, ultimate. Both parties are in constant internal struggle against the forces that wish to subsume this ideal - National Socialism on the Right and Communism on the Left, both battle internally against those extremes. Clinton, for all his faults, ended it on the Left, and Bush, the bastard, is doing everything he can to encourage it on the Right. IMO, true patriots are those on either side of the aisle who believe in the central tenet of individualism over either left or right wing collectivism. There are three unalienable rights, rights which if violated form the right of revolution itself - life, liberty and the pursuit of happiness. Bushism is an attempt to stand that idea on it's head. Your child's life now becomes directed to destruction by the state for commercial needs. Your liberty is now considered second to "security" and the pursuit of happiness, that they will define that for you.
Your idea of how nation's fall is your own. I myself have no crystal ball, but I do know that when America is true to it's original ideals, it wins, when it does not, it loses, because the American system itself is made to be self-correcting. If it withstands the current onslaught against it's ideals, it will stand forever.
But what is most disturbing is your definition of what makes a nation a "success". Jackboots? Terror? Murder? There are plenty of nations that show you to be foolish. Switzerland has stood for a thousand years. Sweden and the rest of Scandinavia have enjoyed centuries of peace and prosperity after withdrawing from European wars 500 years ago. Much of the rest of the world has emerged from WWII and the Cold War into prosperity and peace without the need to murder people for oil. Your idea of "success" is my idea of failure, the return of this nation to the world we were freed from in 1776.