WASHINGTON, D.C. -- An influential U.S. Senate Republican says President Bush's Iraq policy is not working, and he is calling for a downsizing of U.S. forces in Iraq. The comments by Senator Richard Lugar of Indiana has sparked renewed debate about the war, and prompted a second Senate Republican to back the call for a troop withdrawal from Iraq.

Senator Lugar, the top Republican on the Senate Foreign Relations Committee, took aim at President Bush's so-called troop surge strategy in a speech on the Senate floor.

"In my judgment, the costs and risks of continuing down the current path outweigh the potential benefits that might be achieved. Persisting indefinitely with the surge strategy will delay policy adjustments that have a better chance of protecting our vital interests over the long term."

Lugar said current policy is limiting U.S. diplomatic effectiveness around the world and straining U.S. military resources. He urged a draw-down of U.S. troops in Iraq and a redeployment of some of those forces in the region before next year's presidential campaign formally gets under way, when, he says, partisan confrontation would make cooperation on national security nearly impossible.

In making his comments late Monday, Lugar broke with most other congressional Republicans, who have said they would wait to make assessments about Iraq until September, when the top U.S. commander in Iraq, General David Petraeus, delivers a report to Congress.

But Tuesday, another Republican member of the Senate Foreign Relations Committee, Senator George Voinovich of Ohio, joined Lugar in calling for a troop withdrawal. Voinovich sent President Bush a letter expressing his belief that the United States must begin to develop a comprehensive plan for gradual military disengagement from Iraq.

Even before word of Voinovich's letter became public, the Senate's top Democrat, Majority leader Harry Reid of Nevada said Lugar's comments could provide political cover for more Republicans who want to challenge President Bush's Iraq policy.

"When this war comes to an end, and it will come to an end, when the history books are written, and they will be written, I believe that Senator Lugar's words could be remembered as the turning point in this intractable civil war in Iraq," he said.

Next month Reid plans to hold votes on several anti-war related amendments to a defense policy bill, including proposals to cut off money for combat operations, withdraw troops, and revoke the 2002 congressional authorization for the U.S.-led invasion of Iraq.

At the White House, spokesman Tony Snow said Lugar's comments are nothing new, and noted that the senator has had reservations about the surge for some time.

But Lugar told reporters administration officials telephoned him to arrange a meeting with him soon.