Two leading Senate Republican voices on foreign policy criticized President Barack Obama on Sunday for his Afghanistan strategy, saying his plan to begin withdrawing troops in July 2011 is more about politics than national security.

Sen. John McCain (R-Ariz.), the ranking member on the Armed Services Committee, said Obama was “sending the wrong signals” to the people in Afghanistan when he reiterated last week during a speech on Iraq that U.S. troops would begin leaving Afghanistan in a year.

“You cannot tell the enemy you’re going to leave and … expect to succeed. I mean, that’s just a fundamental of warfare,” McCain said on “Fox News Sunday.”

“No military person advised the president to set 2011,” he added. “He did it for political reasons, to take care of his left base. … And that is playing with American lives in a way that I think is absolutely unacceptable.”

During the speech Tuesday marking the end of U.S. combat operations in Iraq, Obama mapped out the plan for withdrawals in Afghanistan. “Next August, we will begin a transition to Afghan responsibility,” he said. “The pace of our troop reductions will be determined by conditions on the ground. … But make no mistake: This transition will begin because open-ended war serves neither our interests nor the Afghan people’s.”

Sen. Lindsey Graham (R-S.C.), who serves on the Armed Services Committee with McCain, said he sees a pathway for limited troop withdrawals within a year but called it wrong for Obama to spell out a timeline. The president should not be saying the United States is “going to withdraw no matter what,” Graham said on NBC’s “Meet the Press.” “I would rather he say, ‘The goal is to transition next summer, we’ll see what the conditions are.'”