On a balmy January day two years ago, President Reagan took office and proclaimed that the United States was gripped by "a crisis" in which government was not the solution, but the problem.

Calling on Americans to join in reducing the size and scope of government, he said, "All of us together--in and out of government--must bear the burden. The solutions we seek must be equitable with no one group singled out to pay a higher price."

Today, as Reagan begins the third year of his embattled presidency, the administration is hearing from pollsters and longtime political supporters that government should be part of the solution to the nation's economic crisis and that the burden of Reagan's economic policies has been shared unequally.

Their message is that the administration is far from finished--"down but not out," in the words of Democratic pollster Peter Hart--but that its opportunities are limited severely by the failure of the economy to respond to Reagan's remedies.

After the Cabinet meeting on Tuesday, one disgruntled administration official said the president and his key advisers do not appreciate the gravity of either the economic situation or the political problems resulting from it.

"I think things are 10 times worse than anyone believes," this official said. "The president and Cap Defense Secretary Caspar W. Weinberger sit around and talk about how workfare got surfers off the beach in California. They have no concept of what is going on."

At this Cabinet meeting, the irrepressible secretary of the interior, James G. Watt, challenged chief economic adviser Martin Feldstein's estimate of low economic growth, saying that supply-side economics is working and that growth will exceed economic forecasts.

"A year ago Ed Meese [White House counsellor Edwin Meese III] would have jumped in the fray and everyone would have been talking it up," said one participant in the meeting. "This time nobody spoke. We're going through the motions. I don't sense fire in anyone's belly, including the president."

This concern has spilled over into Republican ranks outside the White House. Recently, a regional political director in the 1980 presidential campaign sent a memo to White House chief of staff James A. Baker III, saying:

"The difference between 1982 and 1980 is a wholesale substitution of the agenda."

The memo said that inflation and military weakness are the chief concerns of the electorate in 1980, but now have been replaced by Social Security, unemployment and unfairness.

"That's the worst agenda you could imagine for a conservative president," the memo said.

This view is supported by public opinion surveys. Seven months ago the Gallup Poll reported that nearly two-thirds of Americans thought the president didn't care about the poor and more than half thought he didn't care about "the average citizen."

Since then, similar poll results have been carried to the White House by pollster Richard B. Wirthlin, who says he sees the "fairness" question as a continuing problem for the administration.

"The fairness problem is the most severe the president faces," added Republican pollster Robert H. Teeter yesterday. "He does not communicate enough concern and understanding for how badly people are hurting right now."

Reagan's polls also reveal a persistent problem with the electorate on the question of the defense budget and nuclear weapons.

The president lost ground by resisting cuts in the defense budget at a time of domestic economic pain.

Some of his own advisers, reportedly including national security affairs adviser William P. Clark, say they believe that Reagan forfeited the debate on the nuclear freeze issue by agreeing to a recommendation of his political advisers not to discuss it in the fall elections.

Skepticism on this issue may be answered by tangible results in 1983, some Reagan advisers predict.

One said it is the president's "highest hope" that the new Soviet leadership will voluntarily reduce its spending on armaments, even if a treaty reducing nuclear weapons is not achieved which would allow the United States also to cut its defense budget.

If this doesn't happen, officials acknowledge, the administration will face difficult political problems in dealing with arms control and the defense budget.

However, very little skepticism--some would say political reality--finds its way these days into the rosy public statements of the president or those who speak for him.

Reagan's optimism is legendary, and he recently told aides that he thinks the growth rate this year will be higher than Feldstein's forecasts, perhaps as high as 6 or 7 percent.

Today, top White House officials including Baker, Meese, Clark and deputy chief of staff Michael K. Deaver are scheduled to review publicly the first two Reagan years for the press and to pronounce them successful.

The optimistic tone has been enhanced by Reagan's reaction to stories about how he was maneuvered by his staff to do such things as order a cut in the defense budget, and a story in a Texas newspaper in which Baker was quoted as saying that Labor Secretary Raymond J. Donovan should resign.

The president became so angry about these accounts that it encouraged public displays of unity among his top aides and a proliferation of statements that White House cynics call "happy talk."

Judging from the on-the-record comments of key advisers, all the president has to do to succeed in this third critical year of his presidency is to continue doing what he has been doing for the past two years.

"He [Reagan] will do well," said presidential assistant Richard G. Darman. "The budget plan will be credible, balanced, responsible. It will frame the debate and be a basis for constructive negotiations with the Congress."

"Boiling it all down, he has to be able to continue to lead," Baker said this week. "He has done that legislatively the first two years, although he hasn't accomplished everything he set out to do . . . . His budget plan will demonstrate that he is exercising leadership."

Meese said Reagan will continue his present course.

"In terms of style and objectives, I think he has been doing the right things," Meese said. "I don't look for any major changes."

Some administration officials are far more critical when they speak with the understanding that their words will not be attributed to them. But a larger problem, in the view of some familiar with the inner workings of the White House, is that its spokesmen may have begun to believe what they are saying.

"They have focused on leaks to the press and the Hill when they should be focusing on what's happening in the country," said one administration official last week. "This focus fosters an artificial unity in which information is closely held and not everything gets to the president that should."

Some close to the president take a middle ground between the happy talk and the prophecies of doom.

Outgoing Transportation Secretary Drew Lewis is bullish about the economy, and predicted this week that Reagan's position will improve. But he added that, if the economy doesn't turn around, "we're in trouble."

Sen. Paul Laxalt (R-Nev.), a presidential intimate and now general chairman of the Republican Party, said he sees "potential for enormous opportunities" if Reagan shows leadership with Congress and the country.

"I think there's a growing recognition that Ronald Reagan inherited his problems, that he's doing his best and the economic problems were more severe than anyone thought, including him," Laxalt said. "I don't find that the patience of the people is exhausted. FDR kept promising people that it would be better around the corner and people stuck with him."

This is a theme that White House advisers have discussed as a likely one for the president's State of the Union message.

Reagan is expected to repeat many of his familiar aphorisms about staying the course and slaying the budget monster. But now, aides say they want him to suggest that the problems he has inherited are structural, intractable and beyond his control.

Laxalt is Reagan's anchor on the political right, where he faces restiveness and possible revolt.

Although conservatives may have nowhere else to go, for the moment, some already are balking at what they say are the retreats in the Reagan budget--tax increases, the military pay freeze and the increasing emphasis on bipartisanship.

Richard A. Viguerie, fundraiser and spokesman for the New Right, said earlier this week on the Today show NBC,WRC that Reagan probably won't run for reelection. He gave this summary of grievances:

"But it's no secret that a lot of conservatives feel that if the president continues this leftward drift, which recently has almost turned into a stampede . . . of raising taxes, increasing budget deficits, increasing the growth of government, abandoning our allies, such as Taiwan, practicing detente with the Soviets, failing to carry out his campaign promises in . . . stopping busing, restoring school prayers, abolishing the Department of Education, abolishing the Department of Energy, I mean the list is very long of campaign promises he hasn't kept."

What the president actually has done, Reagan advisers acknowledged, is to change the course on which he advised his fellow Americans to stay during the midterm elections.

They say they see him now as appealing to a bipartisan coalition, rather than a conservative one, by reaching an agreement on Social Security funding and acknowledging, by the back door, that some tax increases are necesssary.

"All the rhetoric of the past means nothing now because the proposals the president is pushing today bear no resemblance to what he pushed in 1979 and 1980," one official said last week. "The question is, can he sell mainstream policies to his fellow Americans? He no longer is the carrier of the conservative torch, which he has been for so long."

Even Democrats agree that Reagan repeatedly has demonstrated a surprising resiliency and an ability to change his position while retaining his rhetoric.

Reagan, whose disapproval rating has slipped to 50 percent in the latest Gallup Poll and 61 percent in the latest Harris survey, has a slightly lower standing with the public than former presidents Jimmy Carter and Richard M. Nixon had at the two-year mark. But some pollsters suggest that these numbers may not mean much.

"I don't think that these comparisons mean very much," said Teeter. "Everybody's numbers are down. Fifteen years ago I could have found you 20 governors or senators with 80 percent popularity ratings. Now I doubt I could find three."

The former Democratic national chairman and Carter campaign manager, Robert S. Strauss, says that voters are beginning to blame Reagan for their problems but are not ready to turn against him as an individual.

Strauss tells the story of a union official from a southern state who advised against sending Democrats to denounce Reagan.

"They wouldn't vote for him again, but they sure do like him," Strauss quoted the union official as saying. "They don't want to cuss him."

It is this personal reservoir of good will that Reagan's advisers are banking on as he goes out to face Congress.

"Ronald Reagan has a remarkable ability to do an about-face and appear to be a figure of consistency," said one of his longtime associates.

"He is an achiever, and he has always found a way to achieve."

The statement is an accurate assessment of the political career of a man who repeatedly has been underestimated by his opponents.

Time and again, as governor and presidential candidate, Reagan always has come back.

But this time, even his friends acknowledge, he starts from further back.