That handicap is due to the fact that the USA today doesn't fight defensive wars. It's hard to justify fighting wars happening in the Old World to Americans.

Woodrow Wilson only joined WW1 once the Lusitania was sunk, which caused American deaths. FDR only joined WW2 once Pearl Harbor was attacked. Reagan got away with Grenada because it was a quick and dirty operation. Same with GHWB and First Gulf War. The younger Bush could justify the Afghan invasion only because of WTC, yet even as more Intel dropped on the identity of the terrorists and the lack of progress in locating Bin Laden, domestic support fell.

> But if America stops playing as cautiously as it does, it turns into a very different war machine.

Good luck trying to convince average Americans to do that. On the other hand, the US and Israel have managed to convince the same for the Iranians. They literally rained bombs on the upper class neighborhoods of Teheran, the places where moderates and regime opposition actually lived.