President Reagan said yesterday in an interview with The Washington Post that "the time is too limited" to complete work on a strategic nuclear arms treaty before he meets Soviet leader Mikhail Gorbachev at a Moscow summit this spring.

But Reagan added "that if there is sincerity on both sides with regard to getting such an agreement -- and I think there is" -- a treaty could be signed before he leaves office next January. {Related story, Page A31.}

In the 30-minute interview in the Oval Office, the president repeatedly complimented Gorbachev, whom he compared to Vladimir Lenin, the first leader of the Soviet state. Reagan also said he believes that the Soviets intend to withdraw their troops from Afghanistan, as Gorbachev has announced.

On other issues the president, acknowledging a change in attitude, said that the federal budget deficit, which rose from $79 billion in fiscal 1981 to $150 billion at the end of fiscal 1987, was "a burden" but "not the disaster some people proclaim."

He also defended "as the very soul of integrity" two former close aides, Michael K. Deaver and Lyn Nofziger, who were convicted of illegal activities after they left the White House, as well as Attorney General Edwin Meese III, who is being investigated by independent counsel James C. McKay for his role in a Mideast pipeline project.

And while saying that he would remain neutral in this year's Republican presidential campaign, Reagan effusively praised Vice President Bush, saying that he "has been a part of all that we've been doing" and comparing him to the executive vice president in a corporation.

Reagan's statement that there is not enough time to complete work on a strategic arms treaty before the summit came on a day when contradictory signals emanated from Moscow, where a senior Soviet official said that the accord could be reached in time for the summit. Senior U.S. officials said yesterday that the summit probably will be held late in May, exclusively in Moscow, and last four days.

The president said "it would be nice" if a treaty could be completed by the summit, "but I have to tell you that common sense indicates that the time is too limited for us to really think that we could bring a treaty ready for signature to that meeting."

He added that the proposed pact to reduce the superpowers' strategic nuclear arsenals by 50 percent "is so much more complicated with regard to verification and everything else" than the Intermediate-Range Nuclear Forces (INF) Treaty, which would scrap U.S. and Soviet medium-range and shorter-range nuclear missiles. The INF accord, now awaiting ratification in the Senate, was signed by Reagan and Gorbachev at their Washington summit in December.

One of the obstacles to agreement on a strategic treaty has been Soviet concern about the U.S. Strategic Defense Initiative (SDI), Reagan's plan to develop an antimissile defense system. In the interview, Reagan did not display flexibility on SDI, repeating earlier statements that he would not allow it to be used as "a bargaining chip."

Reagan, who will be meeting Gorbachev for the fourth time in Moscow, said Gorbachev is different from previous Soviet leaders, adding that he had "met most of them." Actually, Reagan has met two of the seven Soviet leaders -- Gorbachev and the late Leonid Brezhnev.

The president said that "one difference is that he {Gorbachev} is the first leader that has come along who has gone back before Stalin and . . . is trying to do what Lenin was teaching." Reagan cited the New Economic Program allowing limited private enterprise that was launched by Lenin in the 1920s and discarded by Stalin after Lenin's death.

Reagan said that Gorbachev's advocacy of glasnost {openness} and perestroika {restructuring} were proposals "much more smacking of Lenin than of Stalin."

In the first news conference of his presidency, on Jan. 29, 1981, Reagan said that the Soviets had since the founding of their state under Lenin reserved "the right to commit any crime, to lie, to cheat," in order to obtain their goal of world domination.

In discussing the prospective withdrawal of Soviet troops from Afghanistan, beginning in mid-May, the president said that "a large part" of the decision was probably based on economic conditions in the Soviet Union. Reagan also credited the fighting prowess of the U.S.-aided Afghan Mujaheddin guerrillas, saying that "they've been a very effective fighting force."

Reagan acknowledged that it is "a reversal of roles" for him to minimize the federal budget deficit, pointing out that he had made speeches for many years deploring excessive government spending. But the president found a silver lining in the deficit cloud, saying that "a great many institutions, universities, educational institutions of all kinds" had part of their endowments in government bonds.

"So, instead of it being something that is just disappearing down a rat hole, it's a kind of a redistribution, you might say, of national wealth in that these institutions and so forth are getting this interest from the government," Reagan said. "Now, maybe some of them would have to be getting straight grants from the government if they were not getting that interest. So, no, I don't think it's disaster. I'm disappointed that we haven't been able to do better."

Reagan said he was "saddened" by what had happened to Deaver, who was convicted of perjury, and to Nofziger, who was convicted of illegal lobbying after prosecutions conducted by independent counsels. He declined detailed comment on their individual cases, which are under appeal, but said, "I want to see them come out all right."

The president repeated an accusation he had made at his news conference Wednesday night that investigations of administration officials, including Meese, were politically motivated.

Asked to review the accomplishments and regrets of his two-term presidency, Reagan singled out the U.S. military buildup as an achievement, saying that it had much to do with bring the Soviets to the bargaining table. He also said that as a result of his attempts to cut domestic government spending "the entire debate has been changed" in Washington.

When asked what he regrets, Reagan first mentioned the 1983 killing of 241 U.S. servicemen, most of them Marines, by a suicide car bomber in Beirut. " . . . The terrible thing was they were actually succeeding in their mission and that's why the violence was turned on them," Reagan said.

In the face of political clamor over this incident, the Marines were withdrawn from Lebanon several months later.

Reagan also mentioned two other tragedies -- the loss of the space shuttle Challenger and the attack on the USS Stark by an Iraqi jet in the Persian Gulf last year -- and talked of "the calls that have to be made to families who have lost someone. . . . Those are things for which you have to be very sorry."

But he turned from this uncharacteristic reflection on the sad moments of his presidency to a more typically optimistic remembrance of the successful U.S. invasion of Grenada in 1983, saying he had recently received a post card from the island that said, "God love the U.S.A."

Reagan concluded the interview by saying that he looks forward to going to Brussels next week, where he will meet NATO leaders and reassure them of U.S. commitment to the Atlantic alliance.

Staff researcher Michelle Hall contributed to this report.