President Bush said yesterday that he has asked Secretary of State James A. Baker III to go to Baghdad and look Saddam Hussein "in the eye" in a final effort to persuade the Iraqi President to withdraw from Kuwait by Jan. 15.

In a morning news conference that was billed as "an address to the nation," Bush said the Baker mission reflected his desire to "go the extra mile for peace" and convince Saddam he is serious about using the authority granted by the United Nations on Thursday to use military force against Iraq unless Saddam withdraws his forces from Kuwait by the January deadline.

Criticized in recent weeks for failing to clearly explain U.S. interests in the Persian Gulf and facing a pivotal phase in the four-month crisis, the president spoke forcefully of his hopes for peace as well as his determination to stop Iraq even if it means war. And he pledged that if U.S. forces are engaged, "There will not be any murky ending."

Bush said he hoped Saddam would meet with Baker "at a mutually convenient time" between Dec. 15 and Jan. 15 and also invited Iraqi Foreign Minister Tariq Aziz to Washington for consultations during the week of Dec. 10.

"We want to make the case to him {Saddam} directly" to comply with the U.N. resolution mandating withdrawal, Bush said, "But it isn't a trip of concession. When you've done what he's done, I don't see that there's room for concession."

For the first time in the gulf crisis, Bush was asked to weigh in personal terms the potential loss of lives in the gulf. Noting the president's love for his five children, a reporter asked, in a dramatic moment at the end of the session, whether the struggle against Iraq was so important to him that he would sacrifice the life of one of them, as he was asking the nation's parents to do.

Taking off his glasses and leaning forward on the podium with a look of distress, Bush spoke of the letters he has received from U.S. troops' wives and mothers and of his resolve that there be enough "firepower" in the gulf to minimize loss of life.

But, said Bush, "the president has to make the right decision, and these are worldwide principles of moral importance. And I will do my level best to bring those kids home without one single shot fired in anger."

There was no official response from Iraq to Bush's offer of diplomatic discussions, but several Iraqi officials expressed relief at what they said was the possibility that there could now be a negotiated settlement of the crisis. {Details, Page A21}.

The idea of a special mission to Iraq has been raised by a number of Democrats -- most recently Rep. Lee H. Hamilton (Ind.) -- and administration officials said Bush began considering it Wednesday, both as a way to quiet domestic critics and out of what one senior official said is Bush's "real belief that Saddam doesn't take this seriously, just doesn't believe we won't back down."

Later in the day, Bush held a lengthy session with congressional leaders to discuss convening Congress in a special session to debate gulf policy. In his news conference, he said the move was up to congressional leaders because he was reluctant to do it himself.

The president was clearly irritated with the hearings the Senate Armed Services Committee held this week in which a number of former high-ranking military officials have questioned the administration's deployment of additional forces in the gulf and the possibility of war. Bush noted that Congress was having "endless hearings by endless experts up there, each one with a different view, and that's the American way."

Pressed on why he would not ask Congress to return to debate his policy, Bush recited the number of members of Congress, that each has a voice and how the voices are mixed on this issue. "They have the power . . . to come back 20 seconds from now and to take a voice, to stand, to take a common position. If they want to come back here and endorse what the president of the United States has done and what the United Nations Security Council has done -- come on, we're ready. I'd like to see it happen."

Bush's outrage over the attempt by Iraqi forces to shut the U.S. Embassy in Kuwait, evident throughout the last few months of the crisis, surfaced again yesterday when he spoke of the "sanctity" of diplomatic buildings.

When it was suggested to him that harming the embassy might be a provocation for war, he said: "Consider me provoked when it comes to the United States Embassy. Consider me provoked when I see Americans without proper food and medical equipment."

Bush disclosed that Iraqi soldiers appeared yesterday morning at the embassy to deliver food and cigarettes and to offer medical care. The president said he is "determined that this embassy . . . be fully replenished and our people free to come home" but said the deliveries may be a positive sign that at least Americans are being better treated.

Bush once again sought to reassure the nation that if the United States goes to war with Iraq, the conflict "will not be another Vietnam. This will not be a protracted, drawn-out war" nor a indecisive conflict, he said.

The deployment of more than 400,000 U.S. troops to the gulf is meant to ensure "that if one American soldier has to go into battle, that soldier will have enough force behind him to win and then get out as soon as possible. I will never, ever agree to a halfway effort."

He also repeated his warning that Iraq is on the verge of developing a nuclear bomb, rejecting the charge by Sen. Albert Gore Jr. (D-Tenn.) and others that Iraq is nowhere near having that capacity and that the president has used that rationale to gain support for his policy. "If he {Gore} wants to gamble on the future about the construction of atomic weapons by Saddam Hussein, I don't," Bush said.

Bush said that even if Iraq withdraws from Kuwait and the government there is reestablished, the issue of Iraq's nuclear capability will have to be addressed. "I think most countries . . . feel that there have to be some safeguards put into effect in terms of guaranteeing the security and stability of the Gulf," the president said.

Bush said the administration has gotten no signal that Saddam might be willing to meet the conditions of the resolutions approved by the U.N. Security Council in response to the Iraqi invasion: immediate and total withdrawal from Kuwait, the restoration of Sheik Jabir Ahmed Sabah's government and the release of hostages.

"I'm not at all hopeful that . . . we'll get good results out of all of this," Bush said of the Baker mission.

The resolution approved by the Security Council Thursday authorizes the use of force after Jan. 15, but the president stressed that date does not mean he must use force at that time. The president said he has asked Aziz, the Iraqi foreign minister, to meet with him and representatives of other nations involved in the multinational force at the White House the week of Dec. 10.

Following the news conference, Bush called the leaders of Turkey, Egypt and Saudi Arabia to brief them and later made similar calls to another half-dozen world leaders.

Officials said Bush made the decision to send Baker on Wednesday after conversations with him, national security adviser Brent Scowcroft and Defense Secretary Richard B. Cheney. Like many such moves in the Bush White House, it was made in secrecy, with no consultations at home or abroad. As Bush was considering the move, his spokesman, Marlin Fitzwater was flatly and vehemently denying that the president would send an envoy to Baghdad.

A senior official said the White House had not signaled the invitations through diplomatic channels beforehand but that administration officials were unanimous in their assessment that Iraq could not turn the chance down. "He's {Saddam} in a box," said one senior official. "How can he say he is not willing to talk?"

On at least six occasions during the news conference, Bush repeated the basic reason for the mission -- that he does not believe that Saddam understands his determination or the meaning of this week's U.N. resolution. "The United Nations resolution, I think, has a good chance of making Saddam Hussein understand what it is he's up against," Bush said. "I have not felt that he got the message. I hope this will do it."

Bush suggested that Saddam may be isolated and kept out of touch with the reality of the military buildup and international unity on the subject. "I am told he is somewhat isolated and I think this U.N. resolution will help to de-isolate him," the president said, adding, "It is a decision that I personally made."

During his meeting with congressional leaders, Bush reacted with what one official called "some force" to Democratic suggestions he should give the economic sanctions imposed on Iraq a year or more to work. One official said he ticked off a dozen reasons why that is not possible, from the condition of the embassy to the added time for Saddam to build up forces, to reject such a long wait.

He made the same point publicly during the news conference. "Those who feel that there is no downside to waiting months and months must consider the devastating damage being done every day to the fragile economies of those counries that can afford it the least," he said.

As he did in a speech Thursday, he specifically mentioned the impact the sanctions are having on the democracies of Eastern Europe and of developing nations of Africa and Latin America.

The format for the Bush appearance was an unusual one. Addresses to the nation are almost always in the Oval Office. But because Bush is uncomfortable with such a setting, he decided to make his presentation in the White House briefing room, a far more casual setting, but insisted that television cameras show only him, with no shots of reporters.