He became a somewhat controversial figure in the conservative movement at the beginning of 2003, when he vocally opposed the impending US war with Iraq. On October 27, 2004, he publicly denounced George W. Bush, saying, "Mr. Bush has become an imperialist—one whose decisions as commander-in-chief have made the world a more dangerous place." Eventually Wanniski endorsed the 2004 Democratic candidate, John Kerry although he clearly preferred the Republican platform on issues related to taxation.