Snyder lost one of her most prominent backers this afternoon when veteran defense lawyer Michael F. Armstrong said that he was so bothered by Snyder's mail and TV ads attacking her opponent that he had decided to switch his allegiance to Vance.

"Leslie is a friend and I called her and told her that this is a pretty fundamental issue and that I'm going to have to switch because of it," Armstrong told the Voice. "Politics is politics, but lawyers have a right to defend clients."

Armstrong, who was counsel to the legendary Knapp commission that probed police corruption in the 1970s, has represented a string of high-profile defendants, most recently Brian McLaughlin, the ex-assemblyman and labor leader who pled guilty to stealing $2 million.

"I think there is a problem in accusing lawyers of being bad guys because they defend bad guys," he said. "It's something that resonates with the public, but in the business we are in everybody knows it is absolutely not true. We all know -- including Leslie -- that you can't ascribe attributes of a client to a lawyer just because he agrees to take a case. The problem is that the public doesn't know that and I don't think it is a good idea to play on that ignorance."

Along with 19 other lawyers, Armstrong also co-signed a letter to Snyder today complaining about the ads. "In multiple mailings to voters, a television ad, and in your remarks at debates and in interviews, you have demeaned Cy's qualifications to be District Attorney because Cy has defended 'criminals'," the letter states. "We are deeply troubled that you would denigrate our obligation as lawyers to defend the accused."

Most of the signers of the letter were already backing Vance. One of them, Robert Gottlieb, said that he was hit by a similar blast of anti-defense lawyer ads when he ran for DA in Suffolk County in 1989. "I've seen first hand how this sort of attack can be effective," he said. "It is the worst kind of pandering. When it happens here you have to speak out especially in a race for DA that is supposed to reflect justice."

Armstrong said that when he spoke to Snyder, the former judge sought to persuade him of the need for the ads. "I had a personal conversation in which she defended herself and I did not find the defense persuasive," he said. "I will let her provide her own explanations."

Snyder's spokesman has yet to respond.

The former judge has aimed most of her fire at Vance, virtually ignoring the third candidate in the race, anti- handgun activist Richard Aborn who has sought to remain above the fray.