When President Reagan was riding high in 1981, he used the congressional budget process effectively to achieve some of his greatest triumphs. The basic machinery has not changed, but Reagan's opinion of it has, largely because what once worked for him now works against him.

Last night, Reagan launched a new appeal for an old set of proposals to change the system -- ideas that many political leaders and analysts say will not break the extraordinary gridlock that has paralyzed debate over spending priorities in recent years.

These analysts and members of Congress say the nation's enormous deficits are a problem of political choices and trade-offs, not a breakdown in the process or the system. They say that changing the process by itself will do little to break the impasse between Reagan and Congress over taxes, defense and domestic spending.

"The problem is we are in a logjam on the basic issues related to budget decisions," said Rep. Leon E. Panetta (D-Calif.), a member of the Democratic budget process revision group in the House. "The president is locked in on defense and taxes and Congress is not going to move on domestic programs. That logjam has been in place for the last four years and process reforms are not going to change that."

"The impasse is inherently a political problem," said Rudolph G. Penner, former director of the Congressional Budget Office and now a senior fellow at the Urban Institute. "What we need is someone to advocate painful choices. There is no process that will take painful choices and make them unpainful."

However, many analysts and lawmakers say the budget "reform" efforts may be worthwhile if they bring Reagan and Congress to the bargaining table on the substance of their disputes. So far this year, Reagan has refused to negotiate with the Democratic-controlled Congress, and last night he sounded a confrontational note in defending his priorities.

In conversations with aides, Reagan claims he was "hornswoggled," as one official put it, in the 1982 tax increase because Congress did not cut domestic spending as much as he had been promised. Many in Congress dispute this, but Reagan insisted recently that he will not negotiate unless any deal is made "enforceable" by Congress.

As a result, White House officials say that some kind of overhaul in the process may ease Reagan's way into negotiation. But they also caution that Reagan appears immovably against tax increases or defense cuts in the final 1 1/2 years of his presidency.

Sen. Pete V. Domenici (R-N.M.), who has introduced a package of budget-process changes, said Reagan "feels he's been burned before" and that as long as the existing system seems "interminable and unenforceable" the chances of negotiation with the president "get more and more remote." Thus, he said, the proposed changes could improve the prospects for serious bargaining.

The budget "reform" effort may also pave the way for repairing the Gramm-Rudman-Hollings balanced budget legislation -- a key portion of which was struck down by the Supreme Court -- and lead to congressional approval for a needed extension of the federal debt limit next month. Congress has set a July 17 deadline for resolving these two issues, and many members as well as top White House aides expect it will produce some kind of companion "reform" package.

Last night, Reagan urged Congress to give him line-item veto authority and approve balanced budget amendment to the Constitution. Both ideas have languished for years and are not likely to be approved now. Presidential spokesman Marlin Fitzwater said yesterday Reagan also favors other "reforms" such as a two-year budget cycle and some mechanism to make congressional decisions enforceable.

These proposals are regarded by budget analysts and members of Congress as incidental to the larger impasse over priorities.

Rep. Willis D. Gradison Jr. (R-Ohio), who is serving on a House Republican task force on budget reform, said, "Budget reform is a reflection of the problem, it's not the problem itself. Budget reform is an attempt to correct a problem which is basically caused by policy disagreements, not process weaknesses."

Gradison said that the standoff between Congress and the White House reflects the American electorate's mixed feelings: They want the deficit reduced, they do not want tax increases and, with some exceptions, they are reluctant to reduce federal domestic spending to any extent. Polls also show voters have grown increasingly skeptical of the need for continuing the Reagan defense buildup.

"I've come to the view that it isn't just a matter of Republicans versus Democrats or the White House versus Congress," Gradison said, "but that the American people themselves are ambivalent about these issues. Through their votes for Congress and the White House they have expressed this indecision or ambivalence. We are just acting out down here what is still unresolved in the voters' minds."

Alice M. Rivlin, a former director of the Congressional Budget Office, said the nation is suffering "a failure of leadership."

"The president and Congress could strike a deal. It has been possible at any time in the last three or four years. But it would take the president saying, 'I'm willing.' . . . The deficit is not one of our most difficult problems. Conceptually we know what to do: raise taxes or cut spending. Everybody has agreed we have to do some of each. It's just a question of putting together a deal. There isn't any process which is going to make this easier or harder."

House Budget Committee Chairman William H. Gray III (D-Pa.) said Reagan's appeal for budget reform is "a smokescreen to avoid dealing with the deficits created by his policies . . . . This administration has been AWOL when it comes to deficit reduction."

"Everybody in this town knows what a farce this is," Gray said. "If this president wants to continue to talk about a line-item veto and a constitutional amendment to balance the budget while his policies double the national debt, that's fine, but the American people are wise to that game."

Staff researcher Michelle Hall contributed to this report.