Vice President Al Gore dispatched a challenge from Senator Bill Bradley of New Jersey early in the 2000 Democratic primaries. Gore chose Senator Joe Lieberman of Connecticut, a prominent intra-party critic of Clinton and the affair with Lewinsky, as his running mate. Texas Governor George W. Bush, the son of former President Bush, won the Republican nomination after defeating Senator John McCain of Arizona in the 2000 Republican primaries. For his running mate, Bush selected Dick Cheney, who had served as Secretary of Defense under George H. W. Bush. Pat Buchanan ran as the Reform Party nominee, and he called for a reduction in immigration. Ralph Nader ran as the Green Party candidate, winning support from many liberals who were disappointed by the centrist tendencies of Clinton and Gore.