The Roosevelt and Truman administrations who conducted WWII were not conservative. As to Korea, Truman shares most of the blame for the unfinished war, as he halted our advance northward in 1951, when we had the Commies on the run.
JFK, who abandoned the Cubans, was not a conservative, and neither was the Democratic congress that cut off funding for South Vietnam and Laos. The Salvadorean government backed by President Reagan, defeated the Communist rebels. However, you may be right about George Bush's mishandling of the Kurdish uprising in Iraq.
I well know they weren’t. After WWII the conservatives were critical partners with interventionist Democrats. So, they were a team. For win or loss. So, how did it turn out?
Not too well.