AFTER almost a week's reprieve, the Clinton administration and its congressional combatants are expected to re-enter the budget battle today.
Yet two of the Republicans' sharpest negotiating tools - the threat of shutting down the federal government and refusing to extend the government's ability to borrow for its own operating expenses - have become blunt instruments, some GOP lawmakers say.
Ohio's John Kasich, the House Budget Committee chairman, has declared that the original strategy of using these techniques to push President Clinton into an acceptable compromise may no longer serve Republican interests. Mr. Kasich is a principal force behind GOP efforts to reduce government's size while devolving power to the states.
The Republican-controlled Congress has already succeeded in getting Mr. Clinton to release his own version of a budget balanced on GOP terms: a seven-year deficit-elimination plan certified by the Congressional Budget Office.
Although the GOP strongly disagrees with the administration's means to that end, it will not risk making Uncle Sam default on his financial obligations, Kasich says. ''My sense is you don't want to mess around with defaulting.''
Public-opinion polls suggest that Americans hold the Republicans more responsible than the White House for the most recent federal government shutdown. Many Republicans are still smarting from this backlash, says freshman Rep. Jerry Weller (R) of Illinois.
''We are not the party to force this government into default,'' asserts one top congressional Republican.
Constrained by Republicans' refusal to add to the current $4.9 trillion in federal debt, Treasury Secretary Robert Rubin has already withdrawn $80 billion from two federal retirement funds in an effort to keep Washington current on its bills. The GOP source says he expects Mr. Rubin's next move will be to tap into the Social Security trust fund for cash.
Some Republican lawmakers, including Gerald Solomon (R) of New York, chairman of the House Rules Committee, have balked at the ''pillaging of retirement accounts,'' and threaten impeachment proceedings against Rubin. Rep. Christopher Shays (R) of Connecticut, known as a more moderate member of his party, insists that the GOP is serious about impeachment prospects.
Meanwhile, with the Feb. 15 date fast approaching for the next big set of interest payments due on Treasury debt, Rubin and his Justice Department colleagues say they are exploring legal means to finance it.
House Speaker Newt Gingrich (R) of Georgia says he plans to sit down with Clinton today to discuss an extension of the debt ceiling but that such a concession will come at a political price. Options range from attaching provisions that would prohibit the Treasury from dipping into government workers' pension funds to linking an increase in the debt ceiling to a new, GOP-sponsored balanced-budget bill, Republican sources say.
Impeachment proceedings ''wouldn't roil Wall Street because we'd view it as something brought on by a radical fringe and not going anywhere,'' says Charles Lemonides, portfolio manager at the New York-based Gruntal & Co. But a default could have serious repercussions for American and foreign investments in US Treasuries. US and overseas investors, he warns, ''will put a higher value on foreign securities relative to US Treasury bills if the US defaults,'' and the US could be hard-pressed for financing.
Donald Straszheim, chief economist at Merrill Lynch in New York, says default would cause a ''major market disruption in the short run. And it would raise interest rates ever more for the United States, because the conclusion would be: If we default once, we can do it again.''
He says all US interest rates are pegged to Treasury notes, because they're considered risk-free. ''Default would push up the premium to borrow higher and the entire economy would suffer.''