In a fresh address to the nation, Mr Bush sought to allay the doubts of some that “the war is lost and not worth another dime or another day”.
He predicted that US training of Iraq’s fledging security forces would pay off, as would fighting corruption.
“…As these achievements come, it should require fewer American troops to accomplish our mission,” said Mr Bush.
“Tonight, I ask all of you listening to carefully consider the stakes of this war, to realise how far we have come and the good we are doing, and to have patience in this difficult, noble, and necessary cause,” he said.
He acknowledged a series of mistakes, starting with the failure to find the weapons of mass destruction at the core of his case for war, but said it is wrong to question whether the conflict is worth it.
Nearly three years after Mr Bush announced the US invasion of Iraq in March 2003, around 2,150 US troops have been killed in mainly insurgent attacks, Mr Bush’s popularity has plummeted, about half of Americans believe the war was a mistake and the cost has run in the billions of dollars.
The latest address comes after four major speeches in which the leader acknowledged setbacks and surprises in the war, and took responsibility for ordering the invasion on the basis of inaccurate intelligence.
The speeches were part of a White House strategy to address complaints the president lacked a solid strategy for the war and has failed to recognise the spiralling violence.
Cheney visits Iraq
Meanwhile, US Vice-President Dick Cheney has made a surprise visit to Iraq, his first since the invasion.
Mr Cheney spoke to US troops, hinting at troop reductions to bring numbers back to 138,000 from the 150,000 that have been deployed there in the run up to last week’s momentous parliamentary elections.
“I think you will see changes in our deployment patterns probably within the next year,” Mr Cheney said.
“I’m encouraged by the tremendous results of the election,” he said, describing the poll which will deliver Iraq’s first full-term parliament since April 2003 as a “major milestone.”
“The new Iraq will become a democratic model for the Middle East.”
“I think when we look back 10 years hence, we’ll see that the year ’05 was in fact a watershed year here in Iraq,” the vice president added.
Elections boost future hopes
Iraq’s fallen Sunni elite, who largely boycotted a vote for a transitional assembly in Januaryhas turned out in force to help determine the make-up of the country’s political representation for the next four years.
US officials are hoping that support shown for the December 15 poll will encourage Sunni, Shi’ite and Kurdish leaders to cooperate on the final drafting of a new constitution.
“The good news is that the Sunnis have now demonstrated that they are determined to be a part of the political process,” US Secretary of State Condoleezza Rice told Fox News Sunday.
“When you talk to Iraqis, they recognise that they need to sustain the momentum out of this election. They need to sustain momentum for the expectations of the Iraqi people,” Ms Rice said, in a warning that Iraq’s leadership should attempt to avoid getting bogged down in drawn-out haggling.
“They need to sustain it because of the insurgency and the terrorists, and they need to get a strong message that the political system is moving forward.”
No US withdrawal timetable
Her comments were made as her predecessor, former US Secretary of State Colin Powell, told the BBC that the US helped fuel the insurgency by failing to gain ground early on in Iraq against looters.
“The plan was after just a couple of months, we would be able to leave. I didn’t share that view,” Mr Powell said.
“I think we lost a lot of time by not imposing our will throughout the country quickly.”
A timetable for withdrawing US troops from Iraq is firmly off President Bush’s agenda, as the US leader refuses to bow to opposition Democrat calls for an exit strategy.
Renewed post-election violence across Iraq has seen at least 17 people killed.
Eleven security force personnel died in a string of bombing and gunfire attacks in and around Baghdad.
In the northern oil city of Kirkuk, gunmen killed the uncle and nephew of a local Kurdish leader.
A woman was killed after a blast outside a Shi’ite mosque in the capital.
Iraqi Vice President Adel Abdel Mahdi, tipped as a possible premier, has called for an end to sectarian bloodshed and for a commitment to building a government of national unity.