"In a time of war, it's irresponsible for the Democratic leadership in Congress to delay for months on end while our troops in combat are waiting for the funds," Bush said in a Rose Garden news conference.

"The bottom line is this: Congress' failure to fund our troops on the front lines will mean that some of our military families could wait longer for their loved ones to return from the front lines," Bush said. "Others could see their loved ones heading back to the war sooner than they need to."

Bush's comments underscored his standoff with Congress. Democrats won power in November, fueled in large part by national anti-war sentiment. They are intent on using their power over money to force Iraq to take more responsibility, and prod Bush to wind down the war.

The president renewed veto threats on both a Senate-passed bill calling for most US combat troops to be out of Iraq by March 31, 2008, and an even stronger House-passed bill demanding a September 2008 withdrawal. He said both bills "undercut the troops."

Bush bluntly said that Congress could not override such a veto.

The president's remarks come one day after Senate Majority Leader Harry Reid (news, bio, voting record), D-Nev., announced he would try to eliminate money for the war if Bush rejects Congress' proposal to set a deadline to end combat.

"It's interesting that Harry Reid, leader Reid, spoke out with a different option," Bush said. "Whatever option they choose, we hope they get home, get a bill, and get it to my desk," Bush said. "And if it has artificial timetables for withdrawal, or cuts off funding for our troops, or tells our generals how to run a war, I'll veto it."

The Senate is in recess this week; the House is on break for two weeks.

The House and Senate are preparing to send Bush a bill by the end of the month that would approve of some $96 billion in new money for the wars in Iraq and Afghanistan, but also set an end date to combat in Iraq. The House wants to order troops out by September 2008, whereas the Senate wants troops to begin leaving right away and set a nonbinding goal of ending combat operations on March 31, 2008.