Clash on Iraq Could Be McCain-Obama Preview

The exchange between McCain and Obama began when the senator from Illinois answered a question by debate moderator Tim Russert, who posed the hypothetical situation of a return to Iraq by al-Qaeda after the United States withdraws troops. Obama said the United States would have to return in that case.

"As commander in chief, I will always reserve the right to make sure that we are looking out for American interests," Obama said in the debate. "And if al-Qaeda is forming a base in Iraq, then we will have to act in a way that secures the American homeland and our interests abroad."

McCain seized on those words, saying they showed a lack of understanding of the terrorist group's activities in the country.

The Sunni extremist group al-Qaeda in Iraq was formed in response to the U.S. presence in Iraq. The U.S. military thinks that the group's activities -- such as large-scale car bombings of Shiite gathering places -- peaked in 2006 and that American forces destroyed much of the organization in a series of raids last year.

The group is "frustrated" but "not defeated," Maj. Gen. Jeffrey W. Hammond, commander of the 4th Infantry Division, said in an interview last month. U.S. officials say that coalition forces have pushed the group largely out of Baghdad and Anbar province, but that it remains active in the upper Tigris River valley.

McCain's attack on Obama's answer is the latest attempt by the Republican to cast Obama as inexperienced on foreign policy. Several months ago, McCain criticized Obama for suggesting that he would bomb al-Qaeda targets in Pakistan without that country's approval.

"The best idea is to not broadcast what you are going to do. That's naive," McCain said earlier this month. "You make plans and you work with the other country that is your ally and friend, which Pakistan is. You don't broadcast and say you are going to bomb the country without their permission or without consulting them. This is the fundamentals of the conduct of national security policy."

Murray reported from Ohio. Staff writer Thomas E. Ricks in Washington contributed to this report.