none as far as I'm aware....
Well, they're invading Iraq, and UK's in Afghanistan but those aren't exactly 'wars' The US is developing many war technologies though so they are very aggressive. They were at war with Iraq, but that technically 'finished'. I don't know so much about the whole Afghanistan situation
Costa Rica has had a civil war, but never a war with other countries.
The US and Germany.
congress
we shouldn't have gone to war with Mexico because all we really wanted was California at the time and Texas came to us to be annexed. It basically was a big misunderstanding between who was on who's land.
Afghanistan was one of the countries.
gerany and japan had both sufferd after the war.
Costa Rica has had a civil war, but never a war with other countries.
I believe that they were involved in the 6 day war with Israel in 1967.
No NATION is at war with the US at this time.
The US Civil War provides the background.
They have gone to war with the Mongols in 1274. Then again with the Mongols in 1281. And then in 1592-1598 Korea and China. Those are all of the ones I can think of right now.
The US and Germany.
Germany Italy japan
congress
Us/ussr
Washington was at war with Hanoi.
Iraq, 2001 and 2003.