I'm not a fan of either party, but this is pretty funny; Democrats have started nearly every American war. (not saying some of these are bad, buuut...)
1812 - Madison was a Democrat-Republican, which evolved into the Democrat party
Mexican-American - Polk was a Democrat, and the war has often been criticized as a "slave war"
Civil War - The mainly Democratic Southern states depart the union after Republican Lincoln is elected
Spanish-American - Finally a Republican, McKinley, takes the British-administered policeman of the western hemisphere to defeat one of the oldest and most powerful nations in western history
WW1 - While not caused by America by any means, Democrat Woodrow Wilson brought America into the war pretty late into the fray
WW2 - Again, not caused by America, Dem. FDR rallied the Depression-stricken populace into beating a bunch of Prussians on steroids alongside a bear, a pansy, and our Parent
Korea - Riding on his predecessor's coattails, Truman defended South Korea
Vietnam - Long, dragged out, and I'm not 100% sure if JFK or LBJ actually started it, but Democrat LBJ spear-headed the troop deployment to the South-Asian country. It's worth noting that a Republican president, Nixon, used an absurd amount of explosives to end the war similarly to Korea. It was only years later when the North attacked again did Congress decline Nixon's demand for war.
Gulf, Iraq, Afghanistan, wars - Bush sr, Bush jr. Republicans. You know the wars, I do, no need to get too detailed.
I'm just saying that, generally, peace means that all is well in the world and America is doing its job properly. In cases such as the second world war, there are reasons to come to the defense of the freedoms of Man, but again, generally war is not the ever-pursued option.
-Chillz