WASHINGTON — Sen. Mike DeWine and Rep. Sherrod Brown sparred Sunday on how best to end the war in Iraq, with DeWine asserting that U.S. troops are in Iraq primarily for U.S. interests, and Brown saying U.S. troops in Iraq are now "for all intents and purposes refereeing a civil war."

During the first of four scheduled debates on NBC's Meet the Press, Iraq and issues of national security dominated the more than 30-minute session. Both men advocate turning over the security situation to Iraqis quickly.

Brown, D-Avon, said the military should be instructed to come up with a strategy to get troops out in 18 months to two years.

DeWine, R-Ohio, said setting a date to exit would only lead to chaos and embolden the insurgents. "Once they are to the point where they can take this over, we're out of there," he said. "We want to be gone."

Brown said without the timeline, DeWine and the Republicans' philosophy is "stay the status quo, stay the course."

"They're not advocating any real change," he said. "They've been saying for three years that things were doing well."

Host and moderator Tim Russert grilled DeWine on his vote supporting the war, asking him if he would have done the same if he had known there were no weapons of mass destruction. "No," DeWine said.

"Do you regret your vote?" Russert asked.

"No," DeWine said.

Instead, he said, the evidence at the time was that Saddam Hussein did have the weapons. He said he voted for the war not just on intelligence, but on "Saddam's history," including gassing the Kurds and eluding United Nations inspectors for years.

But Brown, who voted against the war, was more unequivocal. Neither the president nor then-Secretary of State Colin Powell proved their case, he said. He also said that the international community could have ousted Saddam Hussein by continuing inspections and sanctions.