One trick I have pulled effectively with libs; I ask them,
"so you don't like the way Bush went into Iraq, because he didn't have Congressional approval, he didn't go to the UN, and the stated reason for military action was never proved. Wheras Clinton went to the UN regarding Bosnia, got Congressional approval for Bosnia, and the stated reason was definitively proved correct. Is that right?"
I guarantee 9 out of 10 will say "RIGHT!".
Then, you can have a field day. LOL!
Good one