President Bush issued an unusually blunt appeal to Congress yesterday to approve a resolution authorizing the use of "all necessary means" to drive Iraq out of Kuwait, saying "anything less would only encourage Iraqi intransigence" and erode the international coalition against Iraq.

Bush's request was made in a letter to congressional leaders, who are preparing to open a historic and potentially wrenching debate on the president's Persian Gulf policies. It marked the first time he has formally requested lawmakers to endorse the United Nations resolution ordering Iraq to withdraw from Kuwait by next Tuesday or face possible military action.

The president also criticized Congress for failing to send a clear signal to Iraq. He said an affirmative vote endorsing last November's U.N. Security Council resolution, which set a Jan. 15 deadline after which "all necessary means" can be used to secure Iraq's withdrawal, would have helped Secretary of State James A. Baker III in his meeting with Iraqi Foreign Minister Tariq Aziz today in Geneva.

"It would have been most constructive if he could have presented the Iraqi government a resolution passed by both houses of Congress supporting the U.N. position and in particular Security Council Resolution 678," Bush said in his letter.

Bush said he had "frequently stated my desire" for such a congressional resolution. But until yesterday, despite requests from congressional leaders, he never formally urged Congress to do so.

Showing the resentment of those lawmakers who have called on Bush to seek a resolution, one Democratic leadership aide said, "You don't send {a letter} up Tuesday night and complain" that the requested resolution has not been passed in time for Baker's meeting this morning.

The letter was part of a strategy, which emerged after a day of debate in the White House, to pressure lawmakers who want Bush to give economic sanctions more time to work or who oppose military action.

"We don't like the notion that the president is afraid to go to Congress because of fears he would lose," a senior administration official said. "We need to put that notion to rest."

Vice President Quayle, in a California speech, warned that congressional critics of Bush's policies "have a direct line to Saddam Hussein" through the news media, and said that the Iraqi leader may be getting a message that the president "cannot and will not use force because the Congress will not let him." Quayle said Bush will feel free to use military force regardless of the congressional debate, unless Congress votes to cut off military funding for Operation Desert Shield.

Quayle said U.S. forces in the gulf "don't look forward to spending the next couple of years waiting around in the Saudi desert while Congress debates what to do next."

On the eve of the first high-level talks between the United States and Iraq since the Iraqi invasion of Kuwait Aug. 2, Bush also warned the international community to resist pressures "now building" for a partial solution to the Persian Gulf crisis.

The president, in a seven-minute speech broadcast worldwide by the U.S. Information Agency, said peace on Iraqi President Saddam Hussein's terms would only feed Saddam's "appetite for conquest" and would be "paid many times over in greater sacrifice and suffering."

"The next conflict will find him stronger still -- perhaps in possession even of nuclear weapons and more difficult to defeat," Bush said.

In the taped message, Bush said that next week's deadline is "not a date certain for the onset of armed conflict; it is a deadline for Saddam Hussein to choose, to choose peace over war."

Meanwhile, on both sides of Capitol Hill, Democrats and Republicans were trying to pull together possible language for a resolution while working out the parliamentary situation that would allow for orderly debate and voting.

Among the differing resolution approaches under discussion:

Whether to affirm the U.N. Security Council resolution authorizing "all necessary means" after Jan. 15 to drive Iraq out of Kuwait.

Whether to require a presidential statement or assertion that diplomacy and sanctions have failed to cause Iraq to withdraw from Kuwait, thus requiring the use of force.

Whether to reaffirm that Congress has the sole right to declare war.

"The president wants a blank check which leaves the decision to him when, how, where and what force he can use," Rep. Henry J. Hyde (R-Ill.) said yesterday. "He is not going to get that, clearly."

Hyde, who said he is not involved directly in the negotiations in Congress, said he believes that the House will approve ratification of the U.N. language only "if it requires the president to get further congressional consent before launching hostilities."

In the Senate, lawmakers were discussing two possible votes. The first would explicitly endorse the U.N. resolution, with its "all necessary means" language. The second, which is almost certain to pass, would endorse the use of force at some future time, with the president required to make a determination to Congress that he has exhausted non-military means in the gulf.

Senate Majority Leader George J. Mitchell (D-Maine) said Senate debate would likely begin Thursday, the same day the House starts its debate. House Speaker Thomas S. Foley (D-Wash.) said earlier the House could vote by Saturday.

Mitchell said he hoped Bush's letter "means that the president is finally in agreement with the many members of Congress who have continuously stated that the president needs the approval of Congress prior to any decision to commit the nation to war."

An informal group headed by House Majority Leader Richard A. Gephardt (D-Mo.) spent several hours yesterday discussing language for a resolution that would support Bush's goals in the gulf while encouraging more time for sanctions to work. "The trick is to find the formula to pick up moderates who don't want to rule out force forever, without losing liberals who don't want force at all," one congressional source said.

Separately, House Minority Leader Robert H. Michel (R-Ill.) met with Republicans and Democrats who favor the use of force, trying to craft a resolution that would satisfy the White House and attract enough Democratic votes.

Facing the fluid situation in Congress, administration officials debated whether to ask for a clear endorsement of the U.N. resolution or a more vaguely worded request seeking support of Bush's gulf policies.

Bush said a congressional resolution backing the total of 12 U.N. resolutions passed since the Aug. 2 invasion of Kuwait, and calling for Iraq's unconditional withdrawal from Kuwait, "would greatly enhance the chances for peace."

Senate Minority Leader Robert J. Dole (R-Kan.) took up the administration's line yesterday in a statement saying, "Unfortunately if Tariq Aziz asks Jim Baker, 'What have you brought from Congress?' he'll have to say, 'Nothing.' "

In Saudi Arabia, members of a congressional delegation said they were impressed with the readiness of American troops but disagreed on whether those forces should be used to fight the Iraqis.

"I would support a resolution which supports the position taken by the United Nations," Rep. Dan Burton (R-Ind.) said.

Rep. Charles Hayes (D-Ill.) said: "We should not engage, at this time, in combat. . . . Let's not be so anxious to go to war."

Staff writers Guy Gugliotta in Saudi Arabia, and Ann Devroy, Tom Kenworthy, Walter Pincus and John E. Yang in Washington contributed to this report.