Last fall, a legislative train wreck enabled President Clinton to score big spending and policy victories while leaving congressional Republicans divided and determined never again to give the White House the upper hand.

Eight months later, the Republicans appear headed down the same track again, with no clear idea of how they can avert another political disaster. Divided over budget and tax strategy in a perplexing era of skyrocketing surpluses but tight spending caps, the GOP congressional leaders appear stymied in trying to muster support to begin moving crucial fiscal 2000 spending bills.

The party is being tugged in opposite directions, with some conservatives clamoring for even tighter fiscal constraints to protect Social Security while moderates favor easing up to allow full funding of their pet domestic programs.

House Speaker J. Dennis Hastert (R-Ill.) will try to break the logjam this week, possibly by instructing his appropriators to revise the overall spending scheme to scale back defense and other areas by several billion dollars while providing more for key domestic programs.

"This is something we'll have to work out bill by bill, inch by inch, and sort of slog through," said John Feehery, Hastert's spokesman.

However, Hastert's move is only a short-term palliative, apparently aimed at getting the process started after conservatives blocked votes on three major spending bills late last month.

The danger is his plan may still enrage some conservatives who have been hoping to make political hay out of increases in the Pentagon budget. There's also no assurance he can fully satisfy moderate Republicans or the minority Democrats, whose support he needs to succeed at his strategy but who are not particularly interested in making life easier for Hastert.

Critics complain that the new speaker still has not addressed the more fundamental problem of the inadequacy of funding for domestic programs under the constraints of the 1997 balanced budget agreement. Domestic spending would have to be reduced by nearly $16 billion next year merely to stay within the caps. At the same time, Congress's fiscal 2000 budget falls roughly $30 billion short of what the administration insists will be needed to pass spending bills President Clinton would be willing to sign.

"It's like being on the Titanic and letting the . . . ship go down as long as you move around the deck chairs," James W. Dyer, staff director of the House Appropriations Committee, said of the leadership's approach. "We simply don't have enough money."

Already, the idea of White House officials and congressional leaders returning to the bargaining table to refine the budget deal, as part of a "mini-summit," is beginning to gather steam.

"The reality is that neither party can live with spending caps that were approved in 1997" before the advent of huge surplus projections, said former Congressional Budget Office director Robert D. Reischauer, a proponent of a summit. Reischauer added that it would be good for Clinton and the GOP to "face reality sooner rather than later."

A number of House moderates, including Rep. Michael N. Castle (R-Del.), have discussed the idea, and White House officials informally discussed the possibility of a mini-summit with a Senate GOP aide last week. It could have a little something for everyone, including lifting the spending caps and thus easing GOP efforts to pass the budget and boosting Medicare funding for home health care, skilled nursing and teaching hospitals -- something the administration and some lawmakers would like.

Even Rep. David M. McIntosh (R-Ind.), a leader of House conservatives, said in an interview that high-level talks might be useful in ending the brewing budget crisis. "I don't want to dismiss it out of hand," he said. "There might be some opportunities there."

At the core of the problem is the urgent desire of conservatives to appear purer than Clinton on the issue of preserving the huge surpluses in the politically sensitive Social Security trust fund. Both sides have pledged to adhere to tight spending restraints imposed by the 1997 balanced budget deal, rather than dip into the surplus to finance additional spending.

But in trying to keep that pledge while fulfilling another promise to substantially boost defense spending, Republicans must make deep cuts in a vast assortment of popular domestic spending programs.

GOP leaders tried to finesse the problem by putting off until later this year spending decisions on the largest domestic programs, including labor and health and human services, in the hope that by then additional funds might turn up. But conservatives are indicating they will not go along with that approach, while more moderate Republicans and Democrats say they will not agree to big domestic spending cuts.

The impasse poses a tough leadership question for Hastert, who succeeded Newt Gingrich by promising to make the trains run on time -- but has not yet figured out how to do it. The Senate could face serious problems of its own, but so far Majority Leader Trent Lott (R-Miss.) has damped down discontent by following a spending allocation scheme similar to the one Hastert now wants to promote.

The speaker's problems were on full display last month, shortly before the Memorial Day recess. Hastert was forced to postpone action on the defense authorization bill and spending bills for agriculture and the legislative branch because of a clash with conservative Republicans over budget policy and the war in Kosovo. With only a bare six-vote majority, Hastert found himself at the mercy of a handful of rebellious Republicans.

Rep. Tom Coburn (R), a conservative from Oklahoma, undercut the leadership and tied up the House by trying to attach more than 100 amendments to the $60 billion agriculture spending bill.

Coburn has strong philosophical objections to much government spending and, along with other conservatives, wants Hastert and other leaders to make the difficult budget decisions now rather than cutting a deal down the road that might mean dipping into the Social Security trust fund to finance more spending.

But Castle and other GOP moderates pushing for a summit argue that there will not be enough money to adequately fund all the major spending bills -- particularly those for labor, health and human services, and veterans and housing programs -- and that the leadership's piecemeal approach inevitably will result in another crisis.

"I don't think you can do this by putting down one appropriations bill after another," he said. "At some point you hit the wall and you will end up in the same box we were in last year."

The Republicans and White House resorted to high-level negotiations to craft the 1997 budget deal and then went back to the table late last year to forge a huge omnibus spending package when they could not agree on individual spending bills.

However, White House budget chief Jacob "Jack" Lew insists that the Republicans reconsider some of Clinton's budget proposals they already have rejected before expecting any cooperation from the White House. The White House has proposed raising the tobacco tax and increasing user fees to finance domestic spending in excess of the budget caps.

And many Republicans, including Lott, are wary of resuming talks that might produce a giant bill similar to the one approved last October that was laden with new spending demanded by the administration -- and seen as a big Clinton victory.

Hastert spent part of last week back home considering a number of options for ending the impasse, but congressional aides caution that no decisions will be made until members return to work this week and have a chance to express their views. "As far as I can tell, there is no new strategy in place," a House leadership aide said late last week. "If there is, it's being kept very quiet."

CAPTION: The division within Republican ranks over budget and tax strategy poses a tough leadership challenge for House Speaker J. Dennis Hastert (R-Ill.).