Anti-war Senate Democrats Tuesday plotted a new showdown with US President George W. Bush over Iraq, but admitted they had erred by making supporters think they could end the war.

“On Iraq, we’re going to hold the president’s feet to the fire,” said Senate Majority leader Harry Reid, saying debate would start in two weeks time.

Less than a month after bowing to Bush’s demands and approving a 100 billion dollar war budget, Democratic leaders pledged a new challenge to the White House on withdrawal timelines, troop readiness and curtailing the president’s authority to continue the fight.

Reid said however that Democrats, saddled with a thin majority in Congress, had raised unrealistic expectations about their ability to end the war, among supporters who powered their takeover of Congress last year.

“We set the bar too high,” he said, noting that under Senate rules, Democrats needed 60 votes in the 100 seat chamber to thwart Republican blocking tactics.

On the war, Democratic leaders have only 49 senators in their own party to play with, plus one independent who usually votes with them.

Some Democrats have also been reluctant to make anti-war statements on any bill that provides funding for troops in harm’s way, furthering winnowing the Democratic advantage.

The latest Democratic tactic appeared to be an attempt to keep pressure on Bush and Senate Republicans ahead of an expected critical moment in September, when Congress is due to receive a report on the strategy to surge extra troops into the country.

Even Republicans have warned Bush may have to countenance course correction in Iraq at that time.

Reid, who earlier called for a moment of silence on the floor of the Senate to honor the 3,500th US soldier to die in Iraq, said he would also call for debate on an amendment which sets a goal for combat troop withdrawals by the end of March 2008.

Bush has already vetoed one emergency spending bill that included such a mechanism, and has vowed to block any future attempt by Democrats to tie his hands on the war.

The president forced Democrats to tear troop withdrawal timetables out of the latest war budget which he signed last month.

However, since the new attempt looks set to be attached to an authorization bill, not a war budget in support of the troops — Democrats may be able to attract more Senate support.

An authorization bill obligates money for a government department or agency, while an appropriations bill actually doles out the funding.

Reid said, after meeting senior Senators who are driving his party’s Iraq policy, that he would also call for debate aimed at redefining the 2002 Senate authorization for Bush to wage war in Iraq.

He said freshman Senator Jim Webb would frame an attempt to prevent Pentagon chiefs cutting downtime between deployments for US troops to Iraq — a move which has also been resisted by the administration.

“We may go with something very simple that says: ‘a soldier cannot go back to Iraq until he’s home for the length of time he’s been there.'”

Reid earlier eulogized the 3,500 US troops killed in Iraq, saying “every single one of them is a hero.”

Three US soldiers were killed and six wounded on Monday when their checkpoint was struck by a suicide car bomb, the military said, bringing the overall death toll to at least 3,501 since the March 2003 invasion, according to an AFP count based on Pentagon figures.