Revolutionary War (really should be called the American War of Independence)
Quasi-War (probably should have declared War on France and had a legit war in this case)
War of 1812 (not a great outcome for us, but hey, had to stop the British from impressing our sailors)
Mexican War (
This pretty much sums up why I think we had to do something in this instance)
American Civil War (self-explanatory)
World War I (Germany interfering in Latin American affairs, plus U-boat warfare)
World War II (self-explanatory)
Korean War (North Korea launched a war of aggression against the South, so we had to intervene and drive them out of the country)
Vietnam War (The rationale was good (prevent the Indochinese version of Kim Il Sung from taking over all of Vietnam), but the execution, not so much. Even so, Vietnam is a war I would have supported simply because it was in the context of our larger Cold War efforts against communism)
Operation Just Cause
First Gulf War (same basic issue as Korea)
Bosnian War
Kosovo War
Afghan War (again, rationale was correct, but everything that followed...not so much. We should have gotten the hell out of there after we nixed OBL)
Operation Unified Protector (Libya)