WASHINGTON – Experts on Iraq, who were mostly cold-shouldered by the Bush administration in planning the war, tend not to be among the president’s greatest admirers.

But today, some are surprised to find themselves agreeing with President Bush that a quick U.S. withdrawal from Iraq could lead to “mass killings on a horrific scale,” as the president put it in a news conference this month.

“In spite of the fact that this man is the worst president of my lifetime, occasionally he says something correct and I’m afraid this is correct,” said Peter Sluglett, an Iraq expert at the University of Utah. “While it is superficially attractive to say yes, let’s get out of there, since it was America’s responsibility for getting this mess into Iraq in the first place, it has some responsibility that the thing does not degenerate even further.”

Joost Hiltermann, author of “A Poisonous Affair,” a new book about the Iraqi gassing of the Kurdish town of Halabja in 1988, and a long-standing critic of U.S. policy in Iraq, said he “absolutely” agrees with Bush about withdrawing troops.

“A premature or precipitous withdrawal is very dangerous,” Hiltermann said. “American forces have been the glue to keep together Iraqi security forces. The security forces would totally fall apart, fracture along ethnic and sectarian lines.

“It can get much, much worse. Heavy weapons can be brought in. It’s not scare-mongering to say a precipitous U.S. troop withdrawal would lead to total mayhem that will exceed anything that we’ve seen so far.”

Not all the experts agree.

Juan Cole, a professor at the University of Michigan and perhaps the most outspoken liberal critic of Bush among Iraq specialists, said, “The U.S. troop presence in some areas of the country is probably stirring people up and doing more harm than good. And the foreign military occupation may be prolonging and deepening the eventual conflict.”

But even Cole calls for more political progress before withdrawal, specifically holding local elections in the provinces that were supposed to take place in January 2006.

He said the greatest danger in any withdrawal would be to Baghdad. “When people say things would collapse, they really are talking about Baghdad,” Cole said. “That’s the big issue. Does the Green Zone fall if the U.S. gets out? It’s a possibility.”

Amatzia Baram, an Israeli professor at the University of Haifa and one of the world’s leading experts on Iraq, said the Iraqi government would collapse if the United States withdraws before there is a political settlement in Baghdad allowing former followers of Saddam Hussein to return to government jobs and giving Sunnis their fair share of oil revenues.

“If there is a complete evacuation within a year, the government will not be able to stand on its own,” Baram said.

He said the Kurds probably would grab the oil-rich city of Kirkuk by force, which some people think would lead to a Turkish invasion of Iraq; the Shiite south could split in two, with the southernmost region grabbing 75 percent of Iraq’s oil for itself; fighting probably would break out between Shiite factions throughout the south; and the Sunnis would be forced to continue their civil war and possibly – as Bush predicted – join forces again with al-Qaida to attack the Shiites.

That would lead to the danger of a Shiite massacre of Sunnis that would draw Saudi Arabia, other Persian Gulf states and Jordan into the civil war directly, Baram said.