WASHINGTON - President George W. Bush's goals in Iraq have shifted over the years from reshaping the entire Middle East to defeating Al-Qaeda extremists and keeping the United States safe from terror.

In his latest televised speech on the unpopular war, Bush was set Thursday to announce plans to withdraw roughly 21,500 US combat troops by mid-2008, insisting that his "surge" escalation this year has quelled rampant violence.

"Some say the gains we are making in Iraq come too late," the president was to say, according to excerpts of his address released by the White House.

"They are mistaken. It is never too late to deal a blow to Al-Qaeda. It is never too late to advance freedom. And it is never too late to support our troops in a fight they can win."

When the president unveiled the surge in a prime-time speech from the White House in January, he took the blame for strategic blunders in Iraq and said the situation was "unacceptable."

That compared to December 2005, when in his first televised address to the nation since the invasion, Bush said: "Not only can we win the war in Iraq, we are winning the war in Iraq."

But the definition of victory has evolved down the years into today's emphasis on preventing hordes of Al-Qaeda terrorists from flooding over to the United States.

"Terrorists and extremists who are at war with us around the world are seeking to topple Iraq's government, dominate the region, and attack us here at home," Bush was to say in his speech Thursday.

In February 2003, a month before the US-led invasion, Bush laid out lofty goals for the impending war. "A new regime in Iraq would serve as a dramatic and inspiring example of freedom for other nations in the region," he said.

But in the run-up to the invasion, the US administration argued that Iraqi dictator Saddam Hussein posed an apocalyptic threat to world peace because of his alleged stockpiles of weapons of mass destruction.

"Facing clear evidence of peril, we cannot wait for the final proof -- the smoking gun -- that could come in the form of a mushroom cloud," Bush warned in an October 2002 speech.

Back then, the president was already presenting the hotly contested argument that Saddam had fostered links with Osama bin Laden's Al-Qaeda network and therefore Iraq was a central front of the "war on terror."

As the goal of refashioning Iraq into a liberal democracy faltered, Bush has given new emphasis to the Al-Qaeda connection and to fears of Iranian dominance in the region as justification for continuing the bloody war.

But for Democrats such as Senator Joseph Biden, the Al-Qaeda threat is a "Bush-fulfilling prophecy" created by the Iraq war itself.

House of Representatives Speaker Nancy Pelosi Thursday charged the US public "long ago lost faith" in Bush's strategy "because his rhetoric has never matched the reality on the ground."

The administration has consistently downplayed the insurgency. In June 2003, as roadside bombs and ambushes of US patrols mounted, then defense secretary Donald Rumsfeld dismissed the attacks as the futile work of "dead-enders."

Two years later, Vice President Dick Cheney said the insurgency was "in the last throes" and 12 months on, said Iraq had "turned a corner."

Memorably, Rumsfeld said in April 2003, as violent looting across Iraq devastated vital infrastructure and eroded Iraqis' confidence in their new US overseers, that "stuff happens."

A month after Rumsfeld dismissed the orgy of crime as the price of freedom, Bush landed on a US aircraft carrier to say: "Major combat operations in Iraq have ended." Behind him an enormous banner read: "Mission accomplished."

Nobody today in the US administration says the mission is over. -AFP