Congress should remain committed to deficit reductions required by the Gramm-Rudman-Hollings budget-balancing law even though its automatic enforcement provisions have been declared unconstitutional, President Reagan and key proponents and opponents of the measure agreed yesterday.

The court ruling does not diminish political pressures on Congress to reduce deficits, they said, and underscores the need for a comprehensive budget compromise with the White House.

"The pressure is on," said Senate Majority Leader Robert J. Dole (R-Kan.), who supported the legislation. "We can't run, we can't hide, the court can't save us. It's our budget; we're going to have to live with it or die with it."

"Politically and morally, if not legally, we have an absolute commitment to move toward the $144 billion deficit target" that the law prescribed for fiscal 1987, said Rep. Vic Fazio (D-Calif.), one of 12 House members who brought the suit resulting in yesterday's ruling by a three-judge federal panel. "Now we can do it rationally," Fazio added. "Now we can put that grand compromise together."

But few legislative leaders are willing to predict with any certainty that Congress actually will vote to enact deficit reductions under the fallback provisions that were written into the law in case the automatic trigger was invalidated.

While the law sets out an expedited procedure for enactment of the spending cuts, there is probably "wiggle room," as one budget aide put it, if Congress decides it wants to modify the cuts or avoid a vote altogether.

The ruling revived political maneuvering over the issue that could dominate the session through the November elections.

House Budget Committee Chairman William H. Gray III (D-Pa.), a foe of the legislation, said those who supported it can no longer "hide behind" its automatic provision and must now come up with the spending cuts necessary to meet the targets. "Their own fingerprints will be on the ax," he said.

Presidential spokesman Larry Speakes put the burden for compliance squarely on Congress' shoulders. "It is difficult for us to believe Congress would pass a law . . . then turn around a few weeks later and refuse to live up to it," he said.

Congressional architects of the legislation attempted to minimize the impact of yesterday's ruling by suggesting that the Supreme Court may overturn it and and by trying to make the job ahead appear less painful.

"I'm confident the Congress would pass such a provision carrying out the spending cuts and the president would sign it. There's no turning back now," said Sen. Ernest F. Hollings (D-S.C.), who sponsored the legislation along with Sens. Phil Gramm (R-Tex.) and Warren B. Rudman (R-N.H.). "Gramm-Rudman is as much in effect today as it was yesterday," Gramm said.

In a statement, Reagan said the court decision "does not invalidate Gramm-Rudman-Hollings nor does it diminish the determination of this administration or the responsibility of Congress to meet the Gramm-Rudman-Hollings targets for deficit reduction . . . . "

He pledged to continue submitting budgets that meet the law's targets and added, "All we need to honor both the spirit and letter of Gramm-Rudman-Hollings is congressional action."

Dole and others are exploring the possibility of revising the law to get around constitutional objections to the trigger provision, but no decisions are expected until after the one-week Washington-Lincoln birthday recess that started yesterday. Also under consideration is a move to give congressional sanction to the $11.7 billion in fiscal 1986 spending cuts due to take effect March 1 under the legislation. Such a congressional sanction could foreclose doubts over the legal status of the cuts for this year, regardless of later court rulings.

At a news conference, several of the 12 House members who filed the suit called the court decision a "victory for the Constitution" but said it does not lessen the political imperative to begin reducing the deficit this year.

"We ought to operate on the assumption that we have to meet those [deficit] targets or better them," said Rep. Mike Synar (D-Okla.), who initiated the court challenge. "Although we won, the pressure is now on us more than ever."

Synar predicted that political pressure for deficit reduction will grow regardless of the Supreme Court's ultimate decision in the case. If Congress is forced to vote next fall on an across-the-board budget-cutting measure to meet the deficit target because the automatic trigger mechanism has been struck down by the court, "the political pressure will be so great that when that order hits the floor in all likelihood it will pass," he said.

Some House members renewed their calls for a high-level meeting of congressional and administration leaders, including the president, to work out a compromise budget proposal that meets the $144 billion deficit target.

"We need to hold a domestic summit, the sooner the better, to reach a fiscally responsible, realistic and fair budget," Fazio said.

While the House members stressed that Congress still faces "tough choices" in keeping its commitment to reduce the deficit, few offered concrete suggestions on how to achieve this. Fazio said Congress should consider revenue-raising measures to help meet the deficit target, and Rep. Claude Pepper (D-Fla.) called for an increase in the minimum tax on corporations and wealthy individuals.

Rep. Silvio O. Conte (R-Mass.), the lone Republican among the litigants, used the occasion to assail Reagan's budget priorities.

"We certainly won't meet the deficit targets with major military spending increases," he said. "We certainly won't meet the deficit targets without new revenues."