When President Reagan delivers his State of the Union address tonight he will be speaking to a nation sharply skeptical of his performance, according to a new Washington Post-ABC News public opinion poll.

Reagan's popularity rating is lower than in any previous Post-ABC News poll. For the first time a majority expressed little or no confidence that his program will lead to improvement of the economy. A majority also said Reagan has gone too far in increasing military spending while cutting back social programs.

Even Reagan's income tax cuts and success in reducing the official rate of inflation are discounted. Four of five people polled said the cuts in tax rates have so far made little or no difference in the amount of tax they pay, and a majority said inflation is more of a problem than it was a year ago.

Virtually the only good news in the poll for the president is that Americans still see him as a strong leader, able to push his budget proposals through Congress. And most citizens are as critical of the Democrats as they are of Reagan and the Republicans.

The turn against Reagan comes almost entirely from households where income in the past year has been reduced because of unemployment, layoffs or forced reduction in working hours. Perhaps most striking, according to the Post-ABC News poll, is that a very large number of households in the country, 43 percent, fit one of those categories.

The effect, for Reagan, is:

* A majority of Americans, 54 percent, disapproves of his overall handling of the presidency. Only 42 percent approve of his performance, a striking shift of 17 points since October, when the president was given a 49-to-44 percent favorable rating. Reagan has lost support across the board, from Republicans, Democrats and independents.

* Only four in 10 citizens said they are "very confident" or "fairly confident" that Reagan's program will improve the economy, down from five in 10 who felt that way last October. A majority of 53 percent said they "are not very confident" or "not confident at all" that Reagan's program will help the economy, a marked increase from 43 percent in October.

* Fifty-eight percent said that, where they live, Reagan's presidency has made things worse for people. Only 20 percent said it has made things better.

* For the first time in a Post-ABC News poll, a majority, 54 percent, said Reagan is going too far in his plans to increase military spending. Almost that many, 52 percent, said he is going too far in cutting back social programs. Those figures represent a continued turning away from the president's position since the early days of his administration, when a military buildup and cuts in social programs drew overwhelming support.

Eighty percent said the 1981 and 1982 federal income tax reductions resulted in very little or no reduction at all in the income taxes they pay. Two out of three said those tax cuts favored upper-income people instead.

Most of those who complained about Reagan cited his handling of the economy, but many also expressed concern about his basic goals and judgment.

"He has no concern for the American people," said a man, 24, from southern California who regards himself as a strong Democrat. "He has no idea what he is doing, he's a bad actor playing a 'bad president' act. He slashed education funds, cut off money to people truly in need. He's terrible."

"I think he's out of touch with the middle-class people and definitely the poor people," said a Little Rock woman, 58, also a Democrat. "I know his job is difficult and time-consuming, but they ask for it when they run. He should be on duty more often."

"I feel he doesn't have a strong enough understanding of what's wrong with the country," said a Tucson woman, 73. "He's too rigid to accept advice."

By and large, those who identify themselves as Republicans stayed with the president. But in October, 85 percent of Republicans said they approved his handling of his job and only 13 percent disapproved. Now, approval is down to 74 percent among Republicans and disapproval up to 24 percent.

Scattered through the poll is strong evidence of concern about Reagan's judgment, including on foreign policy and defense.

Asked whether the president should hold a summit meeting with new Soviet leader Yuri V. Andropov "only if Reagan believes something important can be accomplished," or whether the two should meet "even if Reagan believes nothing important can be accomplished," 55 percent said Reagan should meet with Andropov regardless of what Reagan thinks can be accomplished.

Reagan has maintained that development of the proposed MX missile is vital for the country. But among the nine in 10 polled who said they had read or heard about the MX, 51 percent opposed its development and only 38 percent want it.

On the question of whether Reagan or his chief aides are most influential in White House decision-making, 55 percent said Reagan's advisers make "most of the important decisions in the White House" and 35 percent said Reagan makes them.

On the economy, a majority of Americans did not appear to accept the president's contention that "structural problems" are largely responsible for difficulties in making improvements. Instead, by 52 to 37 percent, they took the view that "there are solutions to many of the nation's economic problems, but Ronald Reagan is not using them."

But most citizens failed to see the Democrats offering solutions that are any better than Reagan's or those of the Republican Party. By 60 percent to 31 percent, citizens agreed with the statement that "the national Democratic Party and its leaders criticize the Republicans instead of making their own proposals."

Fifty-one percent blamed the Democrats as much or more than Reagan for the high level of unemployment; only 39 percent blamed Reagan more. Fifty-six percent blamed the Democrats as much or more than Reagan for the current recession; only 39 percent blame Reagan more.

In addition, 37 percent credited Reagan for handling inflation better than the Democrats in Congress. Twenty-five percent said the Democrats are handling the problem better than Reagan, and another 25 percent said both are about equal in their handling of inflation.

But, while Reagan and his supporters have tried to take credit for a sharp reduction in the rate of inflation, the public is still troubled by high prices. Asked whether inflation is more or less a problem than it was a year ago, 52 percent said it is more of a problem, 37 percent said it is less of a problem and 10 percent said it is about as great a problem now as it was then.