Washington ? Republican presidential candidate Rudy Giuliani criticized Democratic front-runner Hillary Rodham Clinton in a full-page ad in Friday’s New York Times, accusing her of assailing Iraq war commander Gen. David Petraeus’ character.

In response, a liberal anti-war group is running a $50,000 ad campaign against Giuliani in Iowa, which begins the presidential nominating process. The television ad from MoveOn.org Political Action, which will start airing next week, accuses Giuliani of a “betrayal of trust” for abandoning the Iraq Study Group.

“Rudy Giuliani has become an uncritical cheerleader for George Bush’s war in Iraq,” said Eli Pariser, the group’s director. “Yet when he had the chance to actually do something about the war, he went AWOL.”

Giuliani joined the Iraq Study Group but only lasted two months, failing to show up for any official meetings. Newsday had reported that Giuliani was a no-show for two of the group’s meetings and instead attended paid public appearances.

Giuliani campaign spokeswoman Katie Levinson said Friday of the upcoming MoveOn ad: “Being attacked by the Democratic character assassination machine MoveOn.org is something Rudy Giuliani will wear as a badge of honor.”

The ad war began Monday, when the Times ran a full-page ad from MoveOn charging Petraeus with “cooking the books” on the Iraq war and playing on his name by asking, “General Petraeus or General Betray Us?” Petraeus was testifying on Capitol Hill, delivering a progress report on Iraq.

Giuliani responded Friday with his own ad in the Times; he attempted to link Clinton to the attack on Petraeus. He also launched an Internet ad against Clinton on his campaign Web site and told voters in Tulsa, Okla., that Clinton should apologize to Petraeus for her “venomous attack.”

“You do not honor the troops by attacking their general at a time of war,” Giuliani said, repeating criticisms he has made since Clinton joined Democrats and some Republicans in questioning Petraeus’ more positive assessment of the war.

At the same time, MoveOn is readying a new TV ad accusing President Bush of a “betrayal of trust,” the same language the group is using against Giuliani.

The MoveOn TV ad argues that, despite plans to withdraw about 30,000 troops added to the U.S. military presence in Iraq earlier this year, Bush remains mired in the war.

“Now he’s making a big deal about, you guessed it, pulling out 30,000 troops,” the ad states. “So next year, there will still be 130,000 troops stuck in Iraq. George Bush. A betrayal of trust.”

The ad against Bush will run from Monday to Friday in Washington on cable and nationally on CNN. The group is spending $60,000 to run the anti-Bush spot.

In Giuliani’s print ad, his campaign quotes him as saying, “These times call for statesmanship, not politicians spewing political venom.”

The Giuliani print ad accuses Clinton, a New York senator, of participating in a “character attack” against Petraeus, citing her comments during a congressional hearing that the general’s progress report on Iraq required a “willing suspension of disbelief.”