Tomorrow, voters in the 50th Congressional District will go to the polls to choose someone to replace former Rep. Randy “Duke” Cunningham, a war hero and popular politician until he was jailed for taking bribes from defense contractors. Candidates have stuffed mailboxes with brochures, paid millions for television commercials, trouped to forums, and constantly pledged to display the integrity Cunningham lacked. But in the past week or so, the tenor of the campaign changed. What had been a largely issue-based race has became a dogfight of negative ads targeting the perceived front-runners: Republican Congressman-turned-lobbyist Brian Bilbray, Republican businessman Eric Roach...