A non-declared war with the french republic, mostly fought on the sea due to our having been allies with the french kingdom.
President James Monroe believed we needed to be distancing ourselves with the affairs of the rest of the world and stated:
"In the wars of the European powers, in matters relating to themselves, we have never taken part, nor does it comport with our policy, so to do."
When the USS Maine was sunk in 1898 the public outcry for response lead to a short lived war between the US and Spain. No one is completely sure what the cause of the ships sinking truly was and many of the tensions may have been unnecessary. Originally this conflict was begun due to Cuba's fight for independence but at that point in time both the US and Spain were looking for a peaceful solution. Once the Maine was sunk though, yellow journalism lead to the public demanding retribution and a 3-month war ensuing.
The US intervened in a war going on between many world powers in Europe. Only in the war for the last few years, this brought the nation onto the world stage as one of the winners.
After seeing the death and destruction of the first world war, the United States attempted to stay out of the second for as long as possible.
Brought into the war by japan with its attack on pearl harbor the united states settled as an Allied power in the war, brining it out of isolation.
Beginning with a rivalry after the second world war, the cold war was a non-conflict and non-declared war in which the US and Russia fought to push their conflicting beliefs through the world.
President Truman's speech on this day set a policy promising to aid Greece and Turkey Economically, marked as the start of the cold war.
A Cold-war fueled conflict that is still a conflict today was fought between the North and South of Korea in a fight for either Democracy or communism. Russia and China Supported the North and the UN the south.
Another Cold-war conflict in which the US and Russia each supported a side in which to either prevent or spread communism.
When Iraq invaded and embargoed Kuwait the UN responded with full force, playing the 'Police officers' of the world.
A peace conference held in Dayton Ohio to end the Bosnian war.
The united states was attacked for the first time since pearl harbor when hijacked planes hit the world trade center, the pentagon, and a failed attack, crash landing in a field. This lead to US involvement in the middle east.