Debates can turn ugly during a hotly contested campaign -- and so can other joint appearances by candidates. When such things happen within a party, that can be a sign that there will be difficulty rallying the troops around the eventual nominee.

That may be the case in Virginia.

The two men vying for the Democratic nomination in Virginia's U.S. Senate race angrily accused each other of being disloyal to their party in a bitter exchange Friday during their first face-to-face meeting of the primary campaign.

Former lobbyist Harris Miller and former Navy secretary James Webb clashed during the taping of what was billed as a casual conversation for "On the Record," a Norfolk television show that will air Sunday morning. The exchange started calmly, with both taking potshots at the man each wants to face in the fall, incumbent Republican Sen. George Allen.

But the conversation quickly turned nasty, with Miller questioning Webb's partisan "values" and Webb noting that Miller had been called by some people "the antichrist of outsourcing." It ended at an impromptu news conference after the taping, with a visibly frustrated Webb telling Miller to "shut your mouth."

The two went after each other on questions of party loyalty -- Webb's support for Republicans in 2000 and Miller's history of campaign contributions to senior Republicans.

The antipathy that had until Friday been reserved for news releases and quiet remarks by campaign aides became personal slams moments into the taping as Miller questioned Webb's support for Republicans during the 2000 election.

"When we were fighting in the trenches to defeat George Bush and George Allen in 2000, you weren't just voting for them, you were endorsing them," Miller said, ignoring the question of the show's host, Joel Rubin.

Webb quickly accused Miller of making inappropriate campaign contributions to senior Republicans in the Congress.

"Why did you donate money to [U.S. House of Representatives Speaker] Dennis Hastert? I've never given money to a Republican in my life," Webb said.

They both claim they will support the other in the general election. But you have to wonder -- will it be an active support? Or will we see the loser retire from the field and offer nothing beyond a few polite words of endorsement at the state convention?