Four months ago Congress passed the Gramm-Rudman-Hollings balanced-budget act amid predictions that it would dramatically alter the way government does business. Today the atmosphere on Capitol Hill is closer to business as usual.

The rhetoric has cooled, important deadlines have slipped away and the House yesterday nearly took up a $1.7 billion supplemental appropriations bill that the Office of Management and Budget calls a "blatant violation" of Gramm-Rudman-Hollings.

The new budget act is not without impact. The Senate began debate Monday on a fiscal 1987 budget that meets the Gramm-Rudman-Hollings deficit target of $144 billion, and departments and agencies are struggling to live with the 4.3 percent across-the-board cuts for fiscal 1986 that took effect on March 1.

But a variety of things have changed the climate on Capitol Hill since Congress voted in December to eliminate the deficit by fiscal 1991.

*In February, a special three-judge panel ruled that a key part of the law that triggers automatic across-the-board cuts is unconstitutional. The Supreme Court will hear oral arguments today on the case.

*An expanding economy and falling interest rates have raised hopes that the deficit may shrink enough to reduce substantially the spending cuts needed to meet the targets for fiscal 1987, although some congressional budget experts contest those predictions.

*Finally, the act of passing the law fostered a curious attitude among some lawmakers that the most difficult step already has been taken.

"It created a false sense of security. . . ," said Rep. Leon E. Panetta (D-Calif.), a veteran of most recent congressional budget wars. "Congress felt it had to take a step [toward curbing deficits], and we took that step. It was Gramm-Rudman.

"It's basically emphasized the bad habits we've gotten into," Panetta added. "Instead of creating pressure to do something, it's taken the pressure off. Instead of setting deadlines, it's undermined deadlines. There's a feeling that if you hang on long enough, the sequestration automatic cutbacks won't be so bad" because economic conditions will have reduced deficits in the meantime.

Ironically, Gramm-Rudman-Hollings was cited as a major factor in Senate refusal to approve a constitutional amendment to force balanced budgets, with both supporters and opponents of the measure contending that the law has eased pressure for passage of the amendment.

Sen. Phil Gramm (R-Tex.), co-author of the legislation, described it as "remarkably successful by any measure." He said he never expected Congress to comply with the deadlines in the law. "The important thing is to start the process rolling two months earlier," Gramm said.

"I don't see any evidence that the heat is off," he added. "People take it very seriously."

Sen. Warren B. Rudman (R-N.H.) contends that even lobbyists are forced to come with offsetting spending reductions when they push their favorite causes, meaning that the budget struggle has become a "zero sum game" that does not add to the deficit.

Indeed, Gramm-Rudman-Hollings passed its first big test in the Senate on March 13, when an effort to exempt farm loans from the law was defeated 61 to 33.

Still, the changed climate appeared to be on the mind of Senate Budget Committee Chairman Pete V. Domenici (R-N.M.) as he opened debate on the fiscal 1987 budget Monday.

To wait for the economy to reduce deficits is "a very high-risk strategy at best" and a "formula for legislative chaos" if it proves unsuccessful, Domenici said, warning that good economic news can add to deficits as well as reduce them. For instance, falling oil prices cut government fuel costs but reduce revenue from oil-related taxes.

For Congress to refuse to make the cuts would be to invite voters in November to say "a pox on both your houses," by throwing out congressional incumbents regardless of party, Domenici added.

Sen. Lawton Chiles (D-Fla.), top ranking Democrat on the budget panel, agreed, calling election day the "ultimate sequester."

The House, meanwhile, has angered the administration by considering an urgent supplemental proposing $1.7 billion in new budget authority without seeking offsetting spending reductions elsewhere, according to the OMB.

Some of the provisions in the supplemental would more than restore the 4.3 percent cutbacks imposed by the first round of Gramm-Rudman-Hollings reductions in March.

House Democratic aides contend that virtually none of the money in the supplemental is to restore the 4.3 percent Gramm-Rudman-Hollings cutbacks except for a small amount transferred from one judicial branch account to another.

Republicans said the restoration question "as a general proposition is on everybody's mind," but hard to prove either way.

For example, the bill would require the administration to "offset" its cherished $702 million embassy security improvement program by taking the money from the Defense Department and foreign aid. The administration is against this.

Congress, for its part, wants to restore some cuts in the Indian Child Welfare Act grant program and to prevent the Veterans Administration from having to furlough employes or conduct a reduction in force. Congress has proposed some transfers to pay for VA programs, but the administration is opposed and says they would cost more.

Both Congress and the White House want an extra $340 million for the Internal Revenue Service "because it was essential that we have a smooth filing season," according to the IRS. The administration has proposed rescissions to make up the difference. Congress has ignored almost all of them