Democratic presidential candidate Joe Biden said Thursday he would move to repeal the authority Congress gave President Bush in 2002 to send U.S. troops into Iraq and replace it with a narrower mandate.

The chairman of the Senate Foreign Relations Committee said the legislation was based on the idea that Iraq had weapons of mass destruction and was designed to oust Iraqi leader Saddam Hussein.

"The WMDs were not there," Biden said in prepared remarks at the Brookings Institution, a private research group. "Saddam Hussein is no longer there. The 2002 authorization is no longer relevant to the situation in Iraq."

The Delaware senator, who voted in 2002 to authorize military intervention in Iraq, said he was working to repeal the authorization and to replace it with "a much narrower mission statement for our troops in Iraq."

Congress should make clear the mission is to draw down U.S. forces in Iraq while continuing to combat terrorists, train Iraqis and respond to emergencies, he said.

"We should make equally clear what their mission is not: to stay in Iraq indefinitely and get mired in a savage civil war," Biden said.

Biden long has criticized Bush's strategy in Iraq. It is not clear whether he would be able to draw enough congressional support to succeed in his effort which also would face a Bush veto.

He renewed his proposed roadmap for a political settlement in Iraq, one that gives its warring factions a way to share power peacefully "and offers us a chance to leave with our interests intact."

"Federalism is Iraq's best possible future," Biden said. "But unless we help make federalism work for all Iraqis, the violence will not stop."