A top lawyer for U.S. President Bush's re-election campaign resigned on Wednesday after disclosing he has been providing legal advice to a group that accuses Democratic presidential candidate John Kerry of lying about his Vietnam War record.

Benjamin Ginsberg was the second person to quit the Bush campaign over ties to the group, Swift Boat Veterans for Truth, which has been attacking Kerry's record through television commercials and a book.

Dispatched by Kerry to defend his service, former Sen. Max Cleland of Georgia and other Vietnam veterans were turned away from Bush's secluded Crawford ranch on Wednesday when they attempted to deliver a letter asking the president to condemn the Swift Boat ads. White House spokesman Scott McClellan dismissed it as a "political stunt."

Bush campaign chairman Marc Racicot had insisted just last week that "there is no connection of any kind whatsoever" between the campaign and the Swift Boat group, and McClellan stood by that assessment despite the Ginsberg revelations.

The Bush campaign has denied Kerry's charge the president's re-election team is using such "front groups." Bush on Monday called for a halt to the ads, along with others run by independent groups, but he did not condemn the group or its allegations.

Ginsberg, who served as the Bush campaign's chief outside counsel for five years, informed the campaign on Tuesday that he has been giving legal advice to the Swift Boat group.

In his letter of resignation to Bush, Ginsberg defended his actions as legal and said he was proud to have advised the veterans. "I have decided to resign as national counsel to your campaign to ensure that the giving of legal advice to decorated military veterans, which was entirely within the boundaries of the law, doesn't distract from the real issues upon which you and the country should be focusing," he wrote.

Ginsberg later told CNN, "Nobody at the Bush campaign or the White House knew of my dual representation," though he did raise the broad issue of representing such groups to the campaign. Ginsberg said he "assumed" the Swift Boat group knew he was working for Bush.

Rep. John Dingell of Michigan, the top Democrat on the House Energy and Commerce Committee, asked the Justice Department to launch a criminal investigation into the "significant ties" between the Bush campaign and the group.

Source: CD/Agencies