President Bush's unexpected decision to preclude a possible visit to Baghdad by Secretary of State James A. Baker III reflected a conclusion by Bush that Iraqi President Saddam Hussein would only use the talks to stall for time, according to high-level administration sources.

The president's hard-line approach yesterday underscored what policymakers describe as his growing impatience with Saddam and his determination not to be humiliated by endless talks with his adversary.

At the same time, by dampening hopes for a diplomatic breakthrough, Bush generated new concern in Congress and among some foreign allies that he is not pursuing all possible alternatives to armed conflict.

"Saddam is playing for the upper hand, that's all he has in mind. Saddam wants to delay and delay and delay us, until we can't shoot," said an administration official, explaining the reasoning behind Bush's announcement that Baker could not go on to see Saddam after meeting with Foreign Minister Tariq Aziz next week.

Although no meeting with Saddam had been set, administration officials had assumed one was likely after Bush's proposal earlier this week that the two foreign ministers meet in Geneva. However, officials said, Bush now believes that Saddam is not interested in productive talks, but rather is trying to string out the diplomacy and play on American domestic opposition to forestall any military attack.

"We've exhausted that option" Bush said curtly of any possible Baker meeting with Saddam, recalling that the Iraqi president had refused to agree to any of the 15 dates he had earlier offered. Bush said he felt Baker could get his point across to Aziz just as well. Privately, officials said Bush was piqued that Saddam had ignored his previous offer, and they said Bush did not want to be vulnerable to further stalling tactics by Iraq.

In recent weeks, administration officials have been particularly worried about a dramatic gambit from Saddam just before the Jan. 15 United Nations deadine for him to pull out of Kuwait, such as a partial withdrawal or a new peace plan. "It would put the ball right back in our court," said one official.

Bush's firm tone reflected what officials have said is his willingness to take the nation to war if necessary. At the same time, the president is struggling to demonstrate to Saddam that he is not bluffing about the use of force and, by his own account, has had a difficult time making that threat credible to the Iraqi leader.

Thus, the no-compromise rhetoric could be part of the psychological war of nerves between Bush and Saddam. It could also mean that the options for a peaceful resolution are narrowing.

Until yesterday, one of the most promising of those options was a face-to-face meeting between Baker and Saddam in Baghdad. The prospects for such a meeting seemed bright earlier in the day when Iraq announced it would accept Bush's offer and send Aziz to Geneva to see Baker. While administration policymakers regard Aziz as a faithful messenger, for weeks they have been saying that a direct Baker meeting with Saddam was critical to demonstrating that all diplomatic possibilities had been exhausted.

The president's announcement yesterday sparked a fresh round of uncertainty in Congress, where many members have urged Bush to try all diplomatic options before resorting to war.

"I think they ought to be creating opportunities to talk to Saddam," not foreclosing on them," said House Armed Services Committee Chairman Les Aspin (D-Wis.), who has generally been supportive of the administration's gulf policy while urging a more active diplomatic effort. "The whole purpose originally was to see Saddam Hussein and get through the sycophantic advisers . . . They are handling this diplomatic initiative so badly I can't believe it."

Aspin said Bush's decision could severely undercut the administration's efforts to build popular support at home for eventual military action. "I think in order to get the American public to believe that war is necessary, you have to show you've tried everything to avoid it. I don't think meeting with Aziz does it; you have to meet with Saddam Hussein."

Rep. James Leach (R-Iowa), a member of the House Foreign Affairs Committee who also has supported Bush, said, "When awesome use of force is contemplated, it is imperative that the public becomes confident that every alternative prospect for dialogue is exhausted."

Although Bush ruled out a Baker session with Saddam, officials said Baker hopes to have full-scale discussions with Aziz in Geneva, not just an exchange of familiar views. "I will say when he begins to go into his litany of why they did what they did, that's really not the issue before us," Baker said in a television interview Thursday.

Baker said he would emphasize the importance of Iraq's compliance with the United Nations resolutions. But, officials said, Baker would also have other items on his agenda, although he would steer clear of any bargaining or negotiations.

One part of Baker's presentation is expected to be a pledge that the alliance would not attack if Iraq pulls out of Kuwait. "When they totally withdraw, there still remain some problems to be solved, but they will not be under attack," Bush said yesterday.

This pledge also carries the threat that if Iraqi troops remain in Kuwait, the international coalition could destroy Saddam and his regime. Baker is expected to try to persuade the Iraqis that their survival dictates a withdrawal from Kuwait.

"I think he's going to be brutally frank and say, 'Does your president know what's arrayed against you?' " said one senior official.

Baker has also said previously that even if Iraq pulls out of Kuwait, there would still have to be a mechanism to constrain Iraq's military might. Officials said Baker could use the session with Aziz to raise the issue of what kind of gulf security arrangements might be put in place later on and whether they would involve continuing sanctions against Iraq.

Finally, Baker and Bush have insisted there be no linkage between a settlement in the gulf and Saddam's demand for an international peace conference on the Middle East. But, officials said, Baker may want to restate the administration's previous policy that at an "appropriate time" -- after the gulf crisis is resolved -- the United States would support such a conference.

Staff writer Tom Kenworthy contributed to this report.