excellent article on US attorney firings
For the time you stumble across the idjit who regurgitates the whiney "But Clinton fired his US attorneys tooooooooooooooo!" (non)talking point, I offer this most excellent primer. It lays it all out, and does so factually without getting into anything heavily partisan (so it should be readable to most people without tripping different reactions to, alternately, "Chimpy" or "Commander in Chief"...)