The Bush administration's unwillingness to publicly estimate either the cost of a possible war with Iraq or the number of U.S. troops that will be required to stabilize the country afterward is triggering complaints among Democrats as President Bush and Defense Secretary Donald H. Rumsfeld work to build support for forcibly disarming the Iraqi regime.

Despite criticism from Sens. Robert C. Byrd (D-W. Va.) and Edward M. Kennedy (D-Mass.), Rumsfeld and his deputy, Paul D. Wolfowitz, have refused to provide even broad estimates of how much a war in the Persian Gulf might cost. They say the range is so great -- depending upon various battlefield contingencies -- that such speculation would be meaningless.

Both senior Pentagon leaders also took exception with an estimate for postwar troop requirements from Gen. Eric K. Shinseki, the Army's chief of staff. Shinseki told the Senate Armed Services Committee on Tuesday that "something on the order of several hundred thousand soldiers" could be necessary.

Rumsfeld, speaking to reporters yesterday at the Pentagon, said he believed Shinseki's estimate "will prove to be high," but declined to say by how much.

"Anyone who tries to go to a single-point answer has to have made a series of judgments about a set of six to eight variables, and he has to have, in his mind, decided, 'Well, this is how that variable is going to be decided, and therefore, I can come to a single-point answer.' " Rumsfeld said. "I'm not deft enough to take six or eight working variables. . . ."

Wolfowitz was far more blunt in testimony Thursday before the House Budget Committee when asked to comment on Shinseki's estimate. "Way off the mark," he said.

Shinseki offered his assessment only after Sen. Carl Levin (D-Mich.) pressed for a "range" of postwar troop levels -- and he did not say that all those troops would be Americans.

Planners on the Army staff, the Joint Staff and Rumsfeld's staff are assuming that, even if 200,000 or more troops are necessary to stabilize postwar Iraq, only a relatively small percentage would come from the United States. Rumsfeld noted this week that numerous allies have indicated that they would commit troops to help stabilize postwar Iraq.

The Joint Staff is estimating that the U.S. troop presence could be between 45,000 and 60,000 soldiers for up to two years, the rough equivalent of two to three Army divisions. While a commitment of this level would put an enormous strain on the Army, which has 10 active-duty divisions, it would be far less than what one Army staff member called Shinseki's "guesstimate."

"The challenge we have is scale and duration, and the fact that it's cumulative when it's added to an already committed Army in Bosnia, Kosovo, the Sinai and Afghanistan," said one Army official. "All that aside, it's doable. The reality is, this is one of the missions the Army does. It is not a lesser case."

A study last year by the Army's Center of Military History has found that the U.S. military would have to commit 100,000 peacekeeping troops in Iraq if it were to occupy and reconstruct the country on the scale that occurred in Japan and Germany after World War II.

One expert, Brookings Institution analyst Michael O'Hanlon, estimates that occupying Iraq -- and holding together its three disparate parts -- could require from 100,000 to 250,000 troops in the first year. Assuming that only 15 percent to 25 percent of that force is American, O'Hanlon recently told the House Armed Services Committee, the Pentagon's contribution would be 15,000 to 60,000 troops.

The Pentagon's unwillingness to talk about the possible cost of the war triggered complaints from Democrats after administration officials disclosed Wednesday that unofficial Defense Department estimates pegged the cost of the war at between $60 billion and $95 billion. That was far higher than Rumsfeld's public estimate five weeks ago, when he said a conflict in the Persian Gulf would probably cost less than $50 billion.

Whatever the cost, military conflict in Iraq will add dramatically to the size of the federal deficit, now estimated at $307 billion.

When Wolfowitz appeared Thursday before the House Budget Committee, Rep. James Moran (D-Va.) accused him of "deliberately keeping us in the dark."

Wolfowitz denied the charge. "We have no idea what we will need until we get there on the ground," he said. "Every time we get a briefing on the war plan, it immediately goes down six different branches to see what the scenarios look like. If we costed each and every one, the costs would range from $10 billion to $100 billion."

Several Budget Committee Democrats said in interviews yesterday they believe the administration is deliberately underplaying the cost of a potential war.

Rep. John Spratt (S.C.), the panel's top Democrat, noted the administration did not include any provisions for a potential war with Iraq and a global war against terrorism. He said lawmakers should be better informed before they press ahead with Bush's budget and tax cut plan.

"They can't say it can't be done. They're shopping it in their own administration," Spratt said. "These costs overhanging the budget ought to have something to do with decisions on spending and tax reduction that will be made over the next few weeks."

Moran was even more blunt. He predicted the administration would later be coming to the Hill with an emergency request for more than $100 billion, leaving lawmakers with little choice but to approve it.

"They treat Congress as if we're just cheerleaders on the sidelines," Moran said. "We're the ones who were entrusted with doling out the taxpayers' money. They seem to have lost all sense of who's supposed to be in charge. We're the elected representatives of the people."

Staff writer Juliet Eilperin contributed to this report.

Soldiers from the 101st Airborne Division await takeoff from Fort Campbell, Ky. The administration has refused to estimate the cost of a war with Iraq.