Bush Asks Support of Congress; Costs Double : Home front: Lawmakers applaud the President’s firm action in the gulf but ask who will pay the bill.

WASHINGTON —  President Bush appealed to members of Congress on Tuesday for political support for his deployment of U.S. forces in the Persian Gulf as the Pentagon doubled its estimate of the early cost of the military buildup to $2.5 billion, triggering new concerns about the huge financial burden that lies ahead.

Addressing more than 100 Congress members in a special briefing with his top Cabinet members, Bush declared that “meeting the crisis in the Persian Gulf is not something that I or this Administration can do by ourselves. We can only succeed if all of us--executive and legislative, Republican and Democrat--work together.”

In the hourlong private session, lawmakers congratulated the President for his firm action but, citing concerns at home, questioned who will bear the mounting costs of what could be a long operation.

The members of Congress also urged Bush to outline more clearly his objectives in taking on Iraqi President Saddam Hussein and pointedly suggested more Administration emphasis on energy conservation to make the United States less at risk from disruptions of gulf oil supplies.

The session--the first broad exchange between the President and Congress since the crisis erupted Aug. 2--delivered both a flag-waving endorsement for the Administration and a warning on serious potential flash points if the overseas commitment drags on.

“The President got high marks for what he has done and the way he has done them,” said House Majority Leader Richard A. Gephardt (D-Mo.). “There was concern, and there will continue to be concern, about where we go from here.”

Participants in the meeting said some lawmakers burst into applause when Sen. Slade Gorton (R-Wash.), in an impassioned praise of Administration action, declared: “Whatever happens, Mr. President, let’s do it right. Let’s win.”

Sen. Joseph R. Biden Jr. (D-Del.), however, told the President that he and other lawmakers who came of age during the Vietnam War era have a different perspective and want to know “what we’re doing in Saudi Arabia” and how long the commitment will last.

Bush, taking questions from a podium in an Old Executive Office Building auditorium so hot that lawmakers jokingly compared it to Saudi Arabia, won praise for his direct responses but generally did not stray from previous public remarks, participants said.

Even when pressed, they reported, the President declined to say whether the United States would accept an outcome in which Hussein withdrew from Kuwait but maintained his power and his military might.

The new Pentagon assessment of early costs of Operation Desert Shield was announced at a Defense Department briefing earlier in the day. The revised $2.5-billion estimate for operations through the end of September--up from $1.2 billion--was attributed largely to the call-up of tens of thousands of reservists and rising fuel costs.

Separately, the Administration told members of Congress it has assembled a new $3-billion arms sale package for Saudi Arabia that will provide the desert kingdom with 24 F-15 fighters, which are among the United States’ most advanced jet aircraft. The reports sparked expressions of concern from members of Congress worried that the equipment would upset the long-term military balance in the Middle East.

Neither the new Pentagon estimate nor the Saudi arms sale was addressed at the Tuesday meeting, which interrupted the vacations of the President and dozens of lawmakers for the first formal briefing to Congress since the Iraqi invasion of Kuwait.

But after reporters were ushered out of the room, participants said, the lawmakers made clear that, however pleased they might have been with the President’s performance, it is the cost of the operation to American taxpayers that is most on their minds.

In an opening question that set a broader pattern, Rep. David E. Bonior (D-Mich.) praised Bush for his “impeccable leadership” but noted that his constituents are complaining that the Japanese, the Australians and others are not doing their fair share.

The recurrent issue, said Sen. Howard M. Metzenbaum (D-Ohio), is whether U.S. allies in Europe and the Middle East will carry their fair share of the burden “or whether they are just going to sit on the grandstand cheering us on.”

According to participants, Bush assured the Congress members that Japan and Saudi Arabia will, in the next few days, unveil plans of their own to help pay for the international operation.

But after he was again pressed on the burden-sharing question, Bush finally declared that he “he would hope that the United States would never be accused of being a mercenary army,” said Sen. Richard G. Lugar (R-Ind.).

“We don’t want other people to pay to put our kids on the line,” California Rep. Robert K. Dornan (R-Garden Grove) told reporters, paraphrasing Bush’s remarks. “We’re doing it because it’s right.”

Members of Congress warned after the session that the huge cost of the operation would all but evaporate an expected “peace dividend” and could severely limit projected budget cuts.

One lawmaker, Sen. Patrick J. Leahy (D-Vt.), said the potential cost to other programs is so severe that he urged Bush to levy a new tax specifically to fund the Persian Gulf mission. Such a measure, he said, would make clear the nation’s willingness to operate on a “pay-as-you-go basis.”

He said Bush had not responded to the proposal, and other Democratic leaders indicated that they regarded the idea as premature.

In another major area of deep concern, lawmakers urged Bush to provide to the American people what Sen. John H. Chafee (R-R.I.) called “as fine an explanation of our presence (in the Middle East) as can be produced.”

Some members warned more specifically that the President cannot count on long-term national support for a military operation justified on grounds of deterring an attack on Saudi Arabia and restoring the sovereignty of Kuwait, the current Administration explanation for the action.

But participants in the session said Bush steadfastly refused to discuss whether his goals in the crisis include the removal of Saddam Hussein. Instead, Secretary of State James A. Baker III obliquely noted that the United States hopes to create “a balance of authority” in the region.

Lugar and others said they were not satisfied by the vague answers. But Metzenbaum said it was “understandable” that Bush would not want to telegraph his hand.

Times staff writers Sara Fritz, Alan Miller, Robert W. Stewart, Karen Tumulty and Maura Reynolds contributed to this article.