Sen. Lindsey Graham, a member of the Senate Armed Services Committee, warned that conservative critics could undermine the U.S. military mission in Afghanistan.

Graham cited recent comments by Republican Party chairman Michael Steele, who called the Afghanistan conflict “a war of Obama’s choosing.”

Steele said the war was “not something the United States has actively prosecuted or wanted to engage in” and alluded to Afghanistan’s reputation as the graveyard of empires.

Graham warned that liberal and conservative war critics could form “an unholy alliance,” during an interview on CNN’s “State of the Union.”

Graham predicted that some Republicans would argue the United States can’t win because President Obama has set a goal of July 2011 to begin withdrawing troops from Afghanistan.

He said some Republicans will say that Obama “made it impossible for us to win, so why should we throw good money after bad, why should any more lives be lost in a hopeless cause because Obama screwed up?”

Graham noted that liberals oppose Obama’s Afghanistan policy because it is a continuation of a war policy set by President George W. Bush, and that liberals also doubt the prospects for success.

“My concern is that for different reasons, they join forces, and we lose the ability to hold this thing together,” Graham said.