Senate Democrats accused the Bush administration yesterday of prematurely rushing to war with Iraq without giving economic sanctions enough time to work, and Secretary of State James A. Baker III faced sharp challenges to his assertion that sanctions are not likely to force Iraqi President Saddam Hussein to withdraw from Kuwait.

Sen. Paul S. Sarbanes (D-Md.), among the most outspoken, said the administration's recent decision to nearly double the U.S. troop commitment to the multinational force in the Persian Gulf region "almost takes you irresistibly down the path of going to war. Now, I cannot say to a family that loses a son or daughter in a conflict that may well take place in the next 60 to 90 days, that we exhausted every possibility for a peaceful resolution before this happened, because the sanctions option has not been exhausted."

Later, the State Department announced that Iraq had formally accepted President Bush's invitation for high-level talks. Iraqi Foreign Minister Tariq Aziz will come to Washington and Baker will go to Baghdad for talks on the gulf crisis, but officials said dates and other details had not been worked out.

Baker told the Senate Foreign Relations Committee that when he meets Saddam, he will not negotiate on the demands of the United Nations that Iraq relinquish Kuwait, restore its legitimate government and free all hostages. He also vowed not to enter talks with Saddam about Palestinians or Lebanon, but he left the door open to discussions about the future of the gulf region.

Separately, CIA Director William H. Webster told a House panel the international trade embargo against Iraq has dealt "a serious blow" to its economy but will probably take up to nine more months to have a significant impact on Iraq's military readiness. Despite mounting disruptions and hardships in Iraq caused by the sanctions, Webster said Saddam "apparently believes that he can outlast international resolve" to maintain them. {Details on Page A43.}

Baker, in his first congressional testimony since the U.N. Security Council voted last week to authorize the use of force against Iraq after Jan. 15, told the Senate committee that the international trade and arms embargoes against Saddam have not influenced the "ruthless dictator" who "undoubtedly believes he can endure economic sanctions." Baker said he remains "very pessimistic" that Saddam will bend to the will of the multinational alliance any time soon, based on U.S. intelligence estimates he did not detail.

"Many countries told us at the outset of this that sanctions would work in a reasonably short period of time . . . inside two or three months," Baker said. "They haven't worked. And as we wait . . . we will, I think, pay a very high price, because by waiting, we will be risking, in effect, a victory for Saddam Hussein.

"As we wait, he is going to be torturing Kuwait further, he is going to be manipulating hostages further, he will be trying to divert attention away to other issues, trying to break up the coalition," Baker said. "The strains on the world economy are not going to get easier, they're going to get worse, the strains on our economy, the strains on the economies of those fledgling democracies in Central Europe. So that's why we are pessimistic."

Baker's statement echoed testimony earlier this week by Defense Secretary Richard B. Cheney, and his approach was generally applauded by Senate Republicans, but it provoked a sustained challenge from Democrats on the committee -- a further indication of the extent to which domestic political opposition is growing to the administration's handling of the gulf crisis.

Democratic senators repeatedly questioned Baker's claim that waiting longer would impose additional difficulties for the anti-Iraq coalition. In response to a statement by Baker that his visit to Baghdad would be "the last best chance" for a peaceful resolution, Sarbanes declared:

"I beg to disagree with you. The last best chance for a peaceful solution . . . is to sustain the sanctions policy for a period of time sufficiently long to give it a chance to work." Sarbanes noted that two former chairmen of the Joint Chiefs of Staff had recently suggested allowing sanctions to work a year or more.

Democrats also criticized Bush's announcement last month nearly doubling the size of the American troop commitment to the multinational force, and they charged that U.S. forces would suffer disproportionately large casualties in any conflict.

They further demanded to know why Saudi Arabia was not using more of its windfall oil revenues -- which they estimated to be $50 billion a year -- to offset the costs of the crisis to the United States and other countries.

Baker said the Saudi contribution to the anti-Iraq effort for this year was substantial and said the administration was studying the financial needs of the coalition. Cheney, speaking to reporters in Brussels yesterday, said he expected that some of the nations in the multinational force would increase their commitments soon, but did not elaborate.

Sen. Joseph R. Biden Jr. (D-Del.) accused the administration of having "abandoned" its policy of a few months ago of letting sanctions put pressure on Saddam. Biden quoted back to Baker his testimony to the Senate panel in September: "What we ask most of the American people is to stand firm, be patient and remain united."

Biden said there is "not one shred of evidence" from any source that Americans are losing their patience, and he demanded to know from Baker which nations in the international coalition were wavering. Baker declined to identify any specific countries but said those who have committed ground troops to the multinational force are prepared to fight alongside the United States.

Responding to the criticism, Baker said "we have not been precipitous, we have not been reckless" in managing the confrontation. But he added that unless the military threat against Saddam is credible, "we will not get a peaceful solution." In his opening remarks, Baker said "our aim is to ensure that if force must be used, it will be used suddenly, massively and decisively."

Several senators urged Baker to consider negotiations with Saddam when he visits Baghdad for a way out of the four-month-old conflict. While Baker rejected the idea of any talks that would reward Saddam's aggression, he did not slam the door on possible future talks about Iraq's complaints against Kuwait over oil and territory or over security arrangements. But he added that such talks would have to be among nations in the region.

Baker said his discussions with Saddam would not be a "show and tell" but rather "a serious effort to try and find a peaceful resolution."

In Baghdad yesterday, Saddam said he wanted Baker to come as a negotiator, not a policeman. "If President Bush or his representative comes to us like a policeman delivering an order, it will mean they have used the talks merely as a cover so they can then persuade Congress they have tried their best," he told a group of European parliamentarians, according to the Iraqi News Agency.

"When they fail to get what the policeman demands, they will consider their mission has reached a dead end," Saddam said. "But if Bush or his representative comes to us as a negotiator, this will mean they really want peace. Iraq wants dialogue, not to be told about orders."