Sen. Paul Laxalt (R-Nev.) moved a long step closer yesterday toward a candidacy for his party's 1988 presidential nomination, telling reporters that if he receives adequate assurances of political and financial support by next spring, "I will go."

The man often called President Reagan's closest political intimate said he no longer feels that he should put his presidential plans aside until his libel suit against The Sacramento Bee has been resolved. Laxalt sued after the newspaper contended that government agents had investigated alleged skimming of profits at his family-owned casino in Carson City. No trial date on the libel case has been set. "I can't let my decisions be bound by other lawyers' timetables," he said.

Laxalt, who is retiring from the Senate, said he has "no crying ambition to go out and run for president," but is being urged by many early Reagan supporters to become a candidate so that "Ronald Reagan's policies and purposes can be perpetuated beyond" 1988.

As chairman of Reagan's presidential efforts in 1976, 1980 and 1984 and general chairman of the Republican Party for the past five years, Laxalt said, "I have lots in place" when it comes to political operatives and allies. But he said he would "need a handle on $8 million or $10 million up front" for his candidacy and that raising such an amount is "an open question."

Laxalt said he has not discussed his possible candidacy with Reagan and assumes that the president will be neutral in the nomination contest. Although his entry would pose serious problems for Vice President Bush and others seeking to claim the Reagan mantle, Laxalt said he thinks "a bitter battle" can be avoided.

Laxalt's name is not widely known outside his home state and Washington, D.C., and he was the choice of only 2 percent of the Republicans and independents in a May Washington Post-ABC News poll. But his history as Reagan's "best friend" in politics makes him a formidable contender in the eyes even of rival candidates' managers.

"Most of the old Reagan team will hold until spring" for his decision, Laxalt said, mentioning such longtime political aides as Lyn Nofziger, Richard B. Wirthlin, Nancy Reynolds and Edward J. Rollins as examples. Rollins, confirming that "all of us would be available," said, "A lot of people are afraid the vice president won't be able to go all the way. They know Laxalt is committed to Reagan's goals, and people who were with him and Reagan are saying, 'Paul, you're the logical successor.' "

Laxalt, 63, said the decision to run would be "a tough call for me," and cautioned reporters that "I'm not nearly there." But after telling The Post last month there was "linkage" between his libel suit and his possible candidacy, he said yesterday that "as far as I'm concerned . . . there is no connection."

The suit was filed in 1984, and Laxalt had expected a trial date by next January. But last week The Sacramento Bee's attorney, Gary Pruitt, requested depositions from more than 10 additional people. While denying Laxalt's charge of using delaying tactics, Pruitt said, "It is going slowly."

Laxalt told reporters he has offered to settle the suit "on the right terms. They print a boxed retraction on the front page and Paul Laxalt is gone," he said. Sources at the newspaper said there had been efforts to settle the case with a public reiteration that Laxalt may have had no knowledge of the alleged skimming, but the senator's demand for an apology and retraction were not acceptable to the paper.

Laxalt said he is prepared to defend legalized gambling and prostitution in Nevada if he enters a national campaign and said he does not think the state's reputation as a wide-open playground would damage his prospects. "Millions of Americans have been exposed to Nevada," he said, "and they've liked and enjoyed what they've seen."

Although well-known to Republican and conservative operatives around the country, Laxalt has rarely been a major figure in public policy debates during his 12 years in the Senate. He came to greatest prominence when he led the opposition to ratification of the Panama Canal treaties during the Carter administration and when Reagan used him as an emissary to Ferdinand Marcos, then president of the Philippines. It was Laxalt who gave Marcos the signal to "cut, and cut clean," which persuaded the strongman that he no longer had enough support to cling to office.