World War Eleven!
Holy Crap! When were the other 9?
Well, if the politicians were the slightest bit honest about declaring/not declaring wars...okay, I'll give you all time to stop ROFLMAO...and counting only the US, I'd happily claim that we're at least up to WWVI, and there are splendid opportunities to add to that count popping up like crabgrass.
Okay, here's my list 3 Korea, 4 Cold War 1.0, 5 Viet Nam, 6 Gulf War & Iraq/Afghanistan (Both half done and could be expanded to whatever we've got to do in the ME to cauterize that mess) and finally Cold war 2.0 (Which should be considered only a relapse of the Cold War 1.0 after the current WH clown posse practically sent engraved invitations to come over and kick us in the teeth)