Republican presidential hopeful Sam Brownback said Tuesday that if the United States pulls out of Iraq too quickly, soldiers will have to return to "clean up an even bigger mess."

"Some people think we can withdraw our troops. But I would remind them of the consequences of failure in Iraq," the Kansas senator said in remarks prepared for delivery on Tuesday night in Des Moines. "Iraq would become a safe haven for Al Qaeda. It would become a failed state and risk a regional war. It would descend into genocidal chaos."

Every day, Americans hear about the bad news in Iraq, making them wonder if it's possible to win the war, he said.

Brownback said the U.S. can win the war, but it will require a political solution — not just a military solution. The key, he said, is for the battling groups in Iraq to reach a "political equilibrium.

"That will allow the Iraqis to drive out the terrorists, build their country and survive in a very tough region of the world," he said. "And, of course, a political solution is the key to reducing threats to our forces, and bringing about stability that will allow us to bring our forces home."