PJ O'Rourke and other libertarians also were against the war You sound confused. P. J. O'Rourke is a solid Republican, and while he might have made fun of some silliness about the way the war was conducted, he didn't oppose it.
My apologies to Mr O'Rourke if I have erred, but a Libertarian page that opposed the war awhile back attributed an anti-war quote to him.