WW2 was a collective effort. Britain did not beg, this is a common misconception. The british were at a stalemate with Germany during this time, both were bombing the shit out of each other. Hitler was targeting the US regardless of whether britain begged or not (U-boats, etc). The US played a historically significant part, of that there is no denying. But they would have been stopped and annihilated at Juno beach were it not for allies taking other strategic locations and for the resistance on the ground providing critical intel, often at the cost of their lives and their families' lives in order for the troops to get a foothold. You should not gloat about the European Theater as much as you think you should. Patton was nothing without help from others and you certainly would NOT have won anything without the help of the russians. Again, a collective effort. On your own you did not do so well in Korea and Vietnam.
More mention goes to your struggles at Guadalcanal and Iwo Jima. That was largely (but again, not completely) a war of attrition between the Japanese and the Americans.
Inb4 "Teh Atomz Bombz" .
All of this has less to do with current events now. It's not necessarily a "US vs everyone" situation anymore. Unfortunately, it's not so black and white as it was in the 40's and 50's. Most countries are somehow now interlinked in almost everything. It becomes a question of the haves versus the have nots and this will always cause conflict. Be it, money, resources such as oil or even in some cases drinking water, famine and religion.
that being said, I'm not a fan of politics, this was just my piece on the matter.