The Obama campaign today said that its supporters should be offended by comments made by conservative billionaire Charles Koch and that his “smears” should “motivate” them to donate to the president’s campaign.

At a private function in June, Koch, who along with his brother David has given millions of dollars to conservative and libertarian causes, used the words of Saddam Hussein to compare the 2012 election to the Iraq War, calling it “the mother of all wars.”

“If that offends you, it absolutely should,” Obama campaign manager Jim Messina wrote in an e-mail to supporters today. “But it should also motivate you, because you are the only thing that can stop them.”

“The Koch brothers and the front groups they fund have decided on the tone they want the election to take in the coming months — and we should expect these kinds of smears to only get worse. But we still have a say about the kind of race we want to run and the kind of political climate we want to create. Take a stand now to support it,” Messina wrote, asking supporters to make a donation of $15 or more.

While the Obama campaign questions the tone set by Koch’s “gutter politics,” the Obama administration has come under fire in recent days for refusing to comment about the remarks of Teamster Union Leader James Hoffa, who called Tea Partyers  ”sons of bitches” when he spoke at a Labor Day event about 20 minutes before President Obama on Monday.

On Tuesday, White House Press Secretary Jay Carney declined to acknowledge that Hoffa’s comments were contrary to the president’s call for increased civility in Washington.

“I understand that there is a ritual in Washington that, you know, somebody says something and you link the associations and then everybody who has an association with him or her … has to avow or disavow it. The president wasn’t there — I mean, he wasn’t on the stage.  He didn’t speak for another 20 minutes.  He didn’t hear it,” Carney said.