WASHINGTON — Republicans escalated a rhetorical war with Democrats over political advertising Thursday as the Senate voted 72-25 to condemn an attack on the U.S. commander in Iraq by the liberal activist group MoveOn.org.

President Bush entered the fray, describing a newspaper ad sponsored by MoveOn.org — which ridiculed Army Gen. David H. Petraeus as "General Betray Us" — as "disgusting."

"I felt like the ad was an attack not only on General Petraeus but on the U.S. military," Bush told reporters at a news conference. "Most Democrats are (more) afraid of irritating a left-wing group like MoveOn.org ... than they are of irritating the United States military. That was a sorry deal."

The full-page ad, published in The New York Times on Sept. 10, the first day Petraeus testified before Congress on conditions in Iraq, has sparked a controversy fueled by Republican politicians who believe it cast a pall over their Democratic opponents.

"The ad was, by any standard, abhorrent," Senate Minority Leader Mitch McConnell, R-Ky., said before Thursday's vote. "It accused a four-star general who has the trust and respect of 160,000 men and women in Iraq of betraying that mission and those troops, of lying to them and to us. Who would have ever expected anybody to go after a general in the field at a time of war, launch a smear campaign against a man we've entrusted with our mission in Iraq?"

MoveOn defended the ad.

"What's disgusting is that the president has more interest in political attacks than developing an exit strategy to get our troops out of Iraq and end this awful war," said Eli Pariser, executive director of MoveOn.org's political action committee. "The president has no credibility on Iraq: He lied repeatedly to the American people to get us into the war. Most Americans oppose the war and want us to get out."

Sponsored by Sen. John Cornyn, D-Texas, the amendment to the defense authorization bill condemned "personal attacks on the honor and integrity of General Petraeus and all members of the United States Armed Forces."

The amendment split Democrats — 22 voted for it, and 24 against. It also split the chamber's two independents, with Joe Lieberman of Connecticut in favor and Bernie Sanders of Vermont opposed.

Sen. Barack Obama, D-Ill., who is seeking the Democratic presidential nomination, did not vote as a protest to what he described as a "stunt designed only to score cheap political points."

"It's precisely this kind of political game-playing that makes most Americans cynical about Washington's ability to solve America's problems," he said in a statement. "By not casting a vote, I registered my protest against this empty politics."

Another Democratic presidential candidate, Sen. Joe Biden of Delaware, also did not vote; his staff said he was traveling in Iowa.

The rest of the Democratic field, including Sen. Hillary Clinton, D-N.Y., voted against the amendment. The two Republican senators running for president — Sam Brownback of Kansas and John McCain of Arizona — voted for it.

One Republican candidate, former Massachusetts Gov. Mitt Romney, immediately used the vote to attack the Democratic front-runner: "Hillary Clinton had a choice. She could stand with our troop commander in Iraq, or she could stand with the libelous left wing of her party. She chose the latter. The idea that she would be a credible commander-in-chief of our armed forces requires the willing suspension of disbelief."