WASHINGTON — Governor Richardson of New Mexico, a Democratic presidential hopeful, said yesterday that he wanted a total withdrawal of American forces in Iraq and that American troops are targets in a civil war.

“I would leave no troops in Iraq whatsoever,” Mr. Richardson said. “The difference between me and the other candidates is, they would leave troops there indefinitely, and I would not.”

He said a U.S. withdrawal should be used as leverage to promote a reconciliation conference of sectarian groups, an all-Muslim peacekeeping force, and a donor conference to rebuild Iraq.

Mr. Richardson says U.S. troops should be redeployed by the end of the year to Afghanistan and the Persian Gulf. Other Democratic presidential candidates also advocate troop withdrawals but leave room for residual forces.

The Bush administration envisions a decades-long American presence in Iraq.

One Republican presidential candidate, Senator McCain of Arizona, said, “We aren’t talking about staying forever.” But he said a long-term training and advisory presence is possible.

“The fact is that if we can withdraw to bases and then eventually close those bases and come home, that’s the plan,” Mr. McCain said.

Mr. McCain said it’s a shame that “September seems to be a magic moment” for deciding whether President Bush’s troop surge in Iraq is working. Mr. Bush is due to receive an assessment then from General David Petraeus, the U.S.commander in Baghdad.

“I’m hoping that he would come back and say, ‘We’ve achieved a certain measure of success,’ to give us some hope and optimism,” Mr. McCain said. “I’m hoping that can happen, but not in my wildest dreams do I expect him to come back and say, ‘Everything’s fine now,’ just a few months after we’ve adopted a new strategy. That would be crazy.”

Mr. Richardson spoke on CNN’s “Late Edition.” Mr. McCain’s interview last week with ABC’s “This Week” aired yesterday.