Members of the House return this week deeply divided about how to shape a new federal budget. There seems to be widespread support for reductions in President Reagan's defense program and very little support for his fiscal 1983 budget, but there is no other clear consensus.

Many members candidly express uncertainty about what to do next. They say that, while Reagan's political support has weakened, he remains popular with their constituents. Many House members seem anxious to find some protection for themselves in an extremely murky political situation.

These are the principal conclusions drawn after 28 interviews with House members throughout the country by Washington Post reporters during the last days of the two-week Easter recess.

The 28 were chosen to reflect the House as a whole, and most of them are middle-of-the-roaders who supported Reagan on at least some of the issues last year.

If this cross-section of House members accurately reflects the feelings of the entire body, it is going to be extremely difficult to build a consensus around any new budget proposal that would significantly reduce the fiscal 1983 federal deficit, now headed as high as $150 billion.

Though many members profess a willingness to compromise and offer a personal agenda for budget changes that would reduce the deficit, these agendas are often flatly contradictory.

"No one likes the president's budget," Thomas E. Petri (R-Wis.) said, "but there's really not a consensus about what to do about it."

For example, James R. Jones (D-Okla.), chairman of the House Budget Committee, said that, after he explains to constituents the problems of the Social Security system and outlines possible remedies, he finds overwhelming support for his proposal to limit this year's cost-of-living adjustment to 4 percent, about half the inflation rate.

"The American people are out in front of the politicians" on Social Security and other issues, Jones said.

Vic Fazio (D-Calif.), a relatively liberal second-term representative, generally agreed, saying that Social Security beneficiaries would accept changes in the program provided others shared in the sacrifice.

But Sid Morrison (R-Wash.), a freshman who supported Reagan on three-fourths of the significant House votes last year, said flatly that Social Security is still an untouchable.

"People have a tendency to panic on that issue," he said. "They've been hearing that the system is in trouble, and then when they hear proposals about cutting down the rate of increase in payments, they assume that the system is being dismantled."

Butler Derrick (D-S.C.) said of his constituents, "They don't want to mess with Social Security one bit."

There are even disagreements on the degree of public concern about budget deficits.

"There's a general recognition that we need to reduce the deficit," Hank Brown (R-Colo.) said. In meeting after meeting with constituents during this recess, "they said get the deficit down," Brown reported.

But Ralph M. Hall (D-Tex.) found that "there's 50 times as much talk about high interest rates as there is about the deficits" and that his constituents tend not to make the connection between the two.

Only on defense spending did most of the members questioned report the same public reaction. Twenty-one of the 28 said their constituents seemed inclined, and many said eager, to reduce the rate of growth of the Pentagon's budget.

According to Charles Pashayan Jr. (R-Calif.), a moderate conservative whom Democrats have hopes of defeating this year, "People are now willing to say, 'Let's slaughter that sacred cow,' " speaking of the defense budget. Businessmen in Buffalo, said John J. LaFalce (D-N.Y.), want defense to be cut.

Harold S. Sawyer (R-Mich), a moderate who supported Reagan last year more staunchly than some other Republicans from his state, said "there is a lot of heat on defense issues" in his district around Grand Rapids, once represented by Gerald R. Ford.

"They think we are spending too much and that we are building up for a war," Sawyer said of his constituents, "and they think that the money could be used to save social programs. There is generally a lack of sympathy for the whole idea of big defense increases ."

"That blank check Reagan thought people gave him for defense now is being reclaimed," Edward J. Markey (D-Mass.) said.

One of the few members who said he did not hear a clamor for cutting the proposed defense budget was Texan Hall. He said he explained to voters that "I'm not going to say cut defense until the commander in chief says it ought to be cut," because only the president has all of the information available to assess the country's defense needs. His constituents accepted that, Hall said.

Not one of the 28 said they thought the president is in deep political trouble, despite the bad economic conditions that all said are a source of grave public concern. But most of them said Reagan had lost significant support since last year, and many seemed genuinely confused about his current political standing.

Pat Roberts (R-Kan.), for example, said the voters in his rural district are "still optimistic Reagan can get the job done," and that "The bottom line is they want me to hang tough with this man." In almost the next breath, Roberts added that many of his voters feel "that we aren't going down the right path" at the moment.

LaFalce, the Buffalo Democrat, felt a similar ambivalence. "He's still well liked," LaFalce said of the president. "I just don't know if he's respected."

"The average guy is not blaming Reagan yet," said Charles F. Dougherty (R-Pa.), "but they're not far from it."

Derrick of South Carolina perceived a class distinction in public reactions to Reagan. "The core of Reagan's support in the business community is still there, and it's solid," Derrick said. "The blue-collar workers, as best as I can gather, have turned" against Reagan.

"One thing that came up almost every time in meetings with constituents was Reagan going on this Caribbean vacation," Derrick said. Many other members reported voter dissatisfaction with Reagan's "working vacation" in Barbados.

Two Democrats whose districts have little in common demographically, Bill Nelson of Florida and Peter A. Peyser of New York, said a moderate Democrat could beat Reagan in their home areas if a presidential election were held today.

Reagan beat Jimmy Carter in Peyser's middle-class Bronx and Westchester County district, 51 to 41 percent, and he won in Nelson's district around Disney World with 62 percent of the vote.

"If the voters were given a choice today between a moderate Democrat like Arkansas Sen. Dale Bumpers or Georgia Sen. Sam Nunn and Ronald Reagan," Nelson said, "they'd go for the Democrat. The business community that was so strong for Reagan is now basically puzzled. The rest of the people are put out with the president. That's a southern colloquialism that means they've had enough."

"I'd say the president running in my district today wouldn't begin to carry it," Peyser said. "The old people are livid with the president, and among students he has no support at this time. I don't know what he's got going for him in the New York area."

Peyser's reference to students was echoed by many of the members. They said last year's cuts in education programs and student loans have angered many voters.

Only a few staunch Reagan supporters stood by him unequivocally in these interviews. One was Gerald B. Solomon (R-N.Y.), who said he was "mildly surprised" by the degree of support he found for Reagan during this Easter recess.

Solomon said the public is still "willing to wait for things to get better. That can be best summed up by a plumber I talked to in Troy who has been unemployed for a year. He told me, 'As far as I'm concerned, if Reagan succeeds, so do I.' "

Three "Gypsy Moth" Republicans, the group of northerners who gave grudging support to Reagan spending and tax cuts last year, indicated that they would not support further cuts in social programs.

Harold C. Hollenbeck (R-N.J.), for example, said it is time to restore some of last year's cuts. "We have to make some adjustments . . . to meet the needs of people who were hurt in the earlier rounds of cuts," he said.

Several members noted that the recession is so serious that even their affluent constituents are feeling it. Bob Shamansky (D-Ohio) said he talked to two Columbus store owners who sell china and other specialty goods to a wealthy clientele. Both reported the first sales declines in 10 years, he said.

Political anxiety was evident in the conversations of many of these congressmen. Asked about prospects in November's congressional elections, Wisconsin's Petri answered:

"Who knows? I voted on Reagan's side 59 percent of the time last year, and against him 41 percent. They can pin some on me, but not the whole rap."