The Bush administration's declaration that Baghdad is in material breach of United Nations disarmament resolutions sets in motion the countdown for a war with Iraq -- but that does not mean that war is inevitable.

The diplomatic and military preparations for an invasion of Iraq to deprive President Saddam Hussein of his weapons of mass destruction are rapidly converging, according to U.S. officials and Middle East analysts. The most frequently mentioned date for an attack is February, a deadline that allows the administration to present a reasonable face to international public opinion even as it finalizes war plans and moves military units into position.

In practice, however, many observers feel there is still wiggle room left for Iraq to avoid a war, despite the seeming finality of the U.S. ultimatum. One widely discussed possibility is a coup that removes Hussein from office before the start of military action. Another is a "deathbed conversion" in which Hussein acknowledges that he does indeed have weapons of mass destruction, and cooperates in giving them up.

After weeks of insisting that Hussein had only one "last chance" to reveal any nuclear, biological and chemical weapons, the Bush administration yesterday effectively gave the Iraqi leader a second chance by delaying the day of final reckoning.

Officials said that a final decision on going to war will probably not be made until Jan. 27, when U.N. weapons inspectors submit a report about Iraqi compliance with Security Council resolutions.

"It just isn't true that war is inevitable, and it's never been true throughout political and military history," said Anthony H. Cordesman, a Middle East expert at the Center for Strategic and International Studies. "If Iraq does something truly dramatic in this period, the administration will have to respond."

Even Republican Party hardliners who have long called for the United States to disarm Iraq by force, even if it means acting unilaterally, acknowledged it would be difficult for President Bush to ignore a last-minute change of heart by Hussein.

"If Saddam says, 'All right, we withheld some things, but we are now prepared to turn them over,' and the administration concluded that his new statement was genuine and comprehensive, would an order be given to launch military action? Probably not," said Richard Perle, chairman of the Pentagon's Defense Policy Review Board. He added, however, that he considers such a possibility "so remote" as to be almost unrealistic.

Other analysts point out that Iraq repeatedly revised statements about its arsenals to U.N. inspectors after the 1991 Persian Gulf War, under the threat of U.S. military action, and could try the same tactic again.

This time around, the "revisions" and "clarifications" would have to be much more dramatic to stave off war, but in theory at least Hussein still has several weeks to bow to U.N. demands.

For weeks, administration spokesmen depicted the Dec. 8 deadline established by Security Council Resolution 1441 for Iraq to issue a report on its weapons programs as the "last chance" for Baghdad to come clean, with no subsequent possibility for revising its declaration.

As President Bush told reporters last month, "we will not tolerate any deception, denial or deceit. Period."

However, Secretary of State Colin L. Powell implicitly recognized yesterday that Baghdad still has the option of giving up its weapons peacefully. "It is still up to Iraq to determine how its disarmament will happen," Powell told reporters.

By leaving the door open to a change of heart by Hussein, the administration is seeking to hold together an international coalition that includes such disparate allies as Britain, Turkey, Kuwait, Qatar and Bahrain.

Without the support, or at least tacit cooperation, of these countries, the logistics of a U.S. invasion of Iraq would be greatly complicated.

"The president may have made up his mind that we are moving to a war with Iraq, but events can always intervene," Cordesman said. "If we cannot bring our allies together, then we may have little choice" but to reconsider.

U.S. allies, including Britain, have so far stopped short of declaring Iraq to be in material breach of U.N. resolutions, the penultimate step on the road to authorizing the use of force.

The administration plans to use the next few weeks to systematically build its case that Hussein still has weapons of mass destruction and has no intention of giving them up peacefully. European governments have already signaled that they want a higher level of proof than simply omissions in the Iraqi declaration.

In an interview earlier this week, Javier Solana, the European Union's foreign policy chief, said the opinion of chief U.N. weapons inspector Hans Blix will be "fundamental" in determining whether European governments will support the United States. "It is very important to produce tangible evidence that can be seen," he said.

European and Middle East support for U.S. war plans cannot be taken for granted, said Ivo H. Daalder, a foreign policy expert at the Brookings Institution. "Our ability to get international support for going to war will be significantly reduced if the Iraqis cooperate with the United Nations in the destruction of their weapons of mass destruction. The president sought international support, and it is difficult for him to walk away from that path now. It might even mean losing Britain."

Martin S. Indyk, a Brookings Institution scholar who is former assistant secretary of state for Middle East affairs, said Washington and Baghdad seem locked into a course for war barring a last-minute change of heart by Hussein. For the administration, he added, the main challenge is now "tactical." It needs to appear as reasonable as possible in order to maintain public support for war, particularly in Europe.

"Saddam's game is clear," Indyk said. "He wants to hide and obfuscate in the hope that public opinion will turn against the war, and he can play out the clock and get us stuck in the inspections trap. I don't believe he will give these weapons up. The corollary is that we are headed for war, sooner or later."