BAGHDAD -- Iraq's security has improved so much, even as U.S. troop levels have dropped, that President Bush seems likely to order thousands more soldiers home by year's end.

That was not the widespread view only three months ago when Bush announced there would be a temporary halt to troop reductions once the last of five "surge" brigades left Iraq this month. Many believed the country would remain too fragile to justify thinning American combat lines before 2009.

However, two weeks of observing U.S. and Iraqi troops in and around Baghdad, coupled with Associated Press interviews with commanders and planners, suggest a likelihood that Bush will move to reduce the U.S. force by perhaps another combat brigade, or roughly 3,000-4,000 soldiers, toward the end of the year.

It now looks as though Bush has more reasons to resume the drawdown than to leave the entire decision to his successor. Not all the reasons are good news: The situation has deteriorated in Afghanistan, and commanders there say they need combat power.

Politically, the Iraqi government is asserting its wish for faster U.S. troop withdrawals. Yesterday the chief spokesman for Prime Minister Nouri al-Maliki said the government hopes the U.S. withdraws its combat troops by 2010.

U.S. domestic political pressures to get out of Iraq are building, too. Democratic presidential contender Barack Obama says he would get all combat forces out within 16 months of taking office. Republican John McCain is opposed to setting any timeline for withdrawals, and says troops will come home as security improves. That's what the White House says, too.

Extra reductions this year might be made by simply canceling plans to replace a combat brigade that is finishing its 15-month tour in Iraq this fall. The departing brigade's operating area most likely would be covered by a unit nearby, spreading it thinner as has been done in numerous instances over the past year.

Fresh reductions this fall would entail some risk of losing momentum toward a stable Iraq.

Despite talk from al-Maliki of ending the dominant U.S. role in his country, interviews with a number of his generals suggest that they are in no rush to see the Americans leave.

Still, arguments for sticking much longer to the current U.S. force size -- now about 147,000 troops -- are losing ground. The Iraqis are showing, in ways not seen even a year ago, that they can handle themselves against the insurgents, whose influence is waning.