and your country, by its own choice, has unproportional share of responsibility for the future of it.

Don't you mean "by its own success"? The last time I checked, a country can't just decide that they're going to be a superpower. Furthermore, most countries which begin to climb the ladder end up falling from grace rather quickly. You phrase your argument as if one day, we just decided we were going to take an "unproportional" share. We *earned* that share. And our responsible use of that power (in most cases) is what allows us to keep it.

The "empire builder" comment is just plain ridiculous, and nullifies your pat-on-the-back about not passing judgements based on prejudice. America might throw its weight around a little bit on foreign policy matters, and mistakes have certainly been made (Vietnam being one of the most recognizable.) But nothing America's ever done has been an effort to build an empire, take over someone else's land, or anything of the sort. I'm not so delusional to think that every move the U.S. has ever made is of the noblest intentions of making the world a better place, but to call us imperialists is taking things a little too far.

This quote from Colin Powell (one of the few in the Bush Administration I respect) sums up how much land the U.S. is after in its world affairs (source)

"We have gone forth from our shores repeatedly over the last hundred years and we’ve done this as recently as the last year in Afghanistan and put wonderful young men and women at risk, many of whom have lost their lives, and we have asked for nothing except enough ground to bury them in, and otherwise we have returned home to seek our own, you know, to seek our own lives in peace, to live our own lives in peace. But there comes a time when soft power or talking with evil will not work where, unfortunately, hard power is the only thing that works."