President George W. Bush has accepted the recommendations of his top commander in Iraq, who said the troop surge is working, and is ordering gradual reductions in U.S. forces there.

In a televised address on Thursday, Bush said the principle guiding his decisions is what he termed "return on success." As he put it, "The more successful we are, the more American troops can return home."

Gen. David Petraeus has recommended that about 2,200 Marines scheduled to leave Anbar Province later this month not be replaced. In addition, Petraeus said it will soon be possible to bring home an Army combat brigade, for a total force reduction of 5,700 troops by Christmas.

Bush said Iraqi leaders "have asked for an enduring relationship with America.

"And we are ready to begin building that relationship in a way that protects our interests in the region and requires many fewer American troops."

But he firmly rejected calls to end the war, saying "the success of a free Iraq is critical to the security of the United States." He said a free Iraq "will deny al-Qaida a safe haven" and will counter what he calls "the destructive ambitions of Iran."

Addressing America's frustration with the protracted war, the president said, "Some say the gains we are making in Iraq come too late. They are mistaken. It is never too late to deal a blow to al-Qaida. It is never too late to advance freedom. And it is never too late to support our troops in a fight they can win."

The reductions announced by Bush represented only a slight hastening of the originally scheduled end of the troop increase that Bush announced in January. When the cutbacks are complete, about 132,000 U.S. forces will be in Iraq.

Democrats Respond

With no dramatic change in course, Bush's decision sets the stage for a fiery political debate in Congress and on the 2008 presidential campaign trail. Democrats said Bush's modest approach was unacceptable.

"An endless and unlimited military presence in Iraq is not an option," said Sen. Jack Reed of Rhode Island, a former Army Ranger, who delivered the Democratic response.

"Democrats and Republicans in Congress - and throughout the nation - cannot and must not stand idly by while our interests throughout the world are undermined and our armed forces are stretched toward the breaking point," Reed said. "We intend to exercise our constitutional duty and profoundly change our military's involvement in Iraq."

House Speaker Nancy Pelosi criticized Bush's plan in a statement released following the president's speech.

"The American people reject the President's call for an 'enduring relationship' with Iraq that is based on leaving our troops in the middle of a deadly civil war for at least 10 years," Pelosi said. "The President failed to answer how maintaining 130,000 soldiers in Iraq would strengthen our military, make us safer, or how he would pay for its additional $700 billion cost."

Senate Democrats on Thursday discussed plans for legislation that would limit the mission of U.S. forces in Iraq. They'd be only allowed to train Iraq's military and police, protect U.S. assets and fight terrorists. But the legislation wouldn't set a deadline to end the war -- perhaps a key to winning support of moderate Republicans.

Iraq Leaders Say Surge Working

Petraeus and Iraq Ambassador Ryan Crocker acknowledged to senators that Iraq remains largely dysfunctional but said violence in recent months had decreased since the influx of 30,000 troops deployed earlier this year.

Crocker said he believed Iraq had "almost completely unraveled" in late 2006 and early 2007. The increased security, if given more time, could pave the way for political reconciliation, he said.

Crocker said he feared that announcing troop withdrawals would focus Iraqi attention on "building the walls, stocking ammunition and getting ready for a big nasty street fight."

Polls Shows Public Disagrees

In contrast to the outlook voiced by Petraeus and Crocker, only 36 percent of 1,000 adults taking part in a new Associated Press-Ipsos poll said the troop increase has helped stabilize Iraq, 4 percent more than a poll taken in February at the start of the troop surge in Iraq.

Fifty-nine percent said they believe history will judge the Iraq war as a failure, including 28 percent who felt it would be rated a complete failure.

And 57 percent said "yes" when asked if it was a mistake for the U.S. to go to war in Iraq, about the same figure as a poll in April.

Only one-third of the people surveyed in a separate AP-Ipsos released Thursday said they are satisfied with the job Bush is doing, and even fewer are pleased with Congress.

Thirty-three percent said they approve of Bush's performance. That essentially matches the all-time low of 32 percent measured several times in the AP-Ipsos survey. The level has barely changed since late last year.

Only 26 percent approve of Congress. The rating is nearly the same as Congress' low point since Democrats took control this year. It measured 24 percent approval in July.

Half of Republicans and GOP-leaning independents, plus large majorities of Democrats and independents, think the country is on the wrong track.

The survey involved telephone interviews with 1,000 adults.