That was certainly true up through the early 2000s, but this stereotype is by now out of date. On the left, America is self-loathing, and on the right it's become quite isolationist.

Terrorist attacks like 9/11 leave doubt about who to go after and at what scale to retaliate but a clear attack on a city by a foreign state as an act of war is a different thing. Gloves would come off and the complete full force of every resource ( military, political, economic, etc ) would be brought to bear.

It depends on the specifics, of course. If a specific country directly attacked the US, of course I'd expect (and even demand) a military response. But these days, I wouldn't expect a non-state's terrorist attack to lead to the sort of misguided, ill-informed adventurism that ultimately led us to invade Iraq.

Also ++ for the use of jingoistic. :)