If the recent exchanges between President Bush, Barack Obama and John McCain on Hamas and terrorism are a preview of the general election, we are in for an ugly six months. Despite his reputation in the media as a charming maverick, McCain has shown that he is also happy to use Nixon-style dirty campaign tactics. By charging recently that Hamas is rooting for an Obama victory, McCain tried to use guilt by association to suggest that Obama is weak on national security and won't stand up to terrorist organizations, or that, as Richard Nixon might have put it, Obama is soft on Israel.