Virginia Gov. John N. Dalton thrust himself into the state's mercurial U.S. Senate race yesterday, apparently cinching the Republican senatorial nomination for his one-time campaign fund-raiser, former Navy secretary John W. Warner.

According to three separate reports, Dalton telephoned Rep. M. Caldwell Butler (R-Va.) yesterday morning as the Roanoke congressman was weighing overtures that he challenge Warner to succeed the late Richard D. Obenshain as the GOP Senate nominee.

Less than two hours later, Butler formally withdrew from the race.

"He told me to do something," Butler said later. "He said he didn't want to foreclose anybody's options, but he hoped I would either get in the race or get out. So I got out."

Dalton met later in the day with Warner for about 40 minutes, after which Warner announced he would hold a news conference today in the governor's news conference room in the state capitol.

The former Navy secretary thus appeared to edge past the last remaining obstacle in his effort to succeed Obenshain, who was killed last week, in a plane crash near Richmond while returning from a campaign engagement.

The GOP State Central Committee is scheduled to meet at 2 p.m. Saturday in Richmond to select Obenshain's replacement. The committee's choice will oppose Democratic former Virginia attorney general Andrew P. Miller in the race for the Senate seat being vacated by Republican Sen. William L. Scott.

Few committee members have professed enthusiasm for Warner, the wealthy sixth husband of actress Elizabeth Taylor, though he finished a close second behind Obenshain in the GOP state convention in June and with his wife raised thousands of dollars for Dalton's campaign last year.

Skeptical of his credentials both as a Virginian and as a conservative, old-line leaders in the business and political coalition loyal to Obenshain have searched frantically in the past few days for an alternative.

But after Butler's withdrawal one Obenshain staffer said wearily, "There just seems to be a drift to this thing now, and there seems to be only one way it can go."

Warner's personal fortune, which appeared to give him the edge on other candidates all along, apparently was a deciding factor. "We're a hundred yards and a million dollars behind in this race now," Butler said. "I didn't have the personal connections to get that kind of money as fast as we would need it . . . Why knock yourself out trying?"

Butler and others in the party were also concerned that the sort of efforts necessary to raise the needed money and launch Butler's candidacy at this date might endanger the coalition and party unity Obenshain had labored so long to build.

The 6th District congreeman had been an eleventh-hour choice of party leaders as an alternative to Warner, but said he was never formally approached by them and added: "You'd be surprised how few people have told me I made the wrong decision" by bowing out.

Dalton's precise role in the Warner campaign remained unclear. The governor left Richmond for a meeting in Roanoke shortly after the meeting with Warner and was scheduled to spend the night at his home in Radford.

But one key strategist in his gubernatorial campaign, Ed De Bolte, was already at work for Warner and another, executive assistant William Royall - his campaign director - was reported ready to take a leave of absence and direct the Warner effort.

Butler said he interpreted Dalton's phone calls - an aide said he spoke with the governor several times - as neither encouraging nor discouraging his candidacy. "But then I wasn't looking for any advice," he added. "I'm old enough to make up my own mind."

After meeting for little more than an hour with Dalton, Warner went to Obenshain headquarters for a briefing on the campaign organization so far. He also huddled with Obenshain campaign director and Virginia GOP national committeewoman Judy Peachee.

"I met this morning very briefly with former governor Linwood Holton and he offered me his warmest congratulations," Warner said between meetings in Richmond yesterday.

Also receiving a briefing was State Sen. Nathan Miller of Bridgewater, who yesterday said he was still holding open a decision on whether to oppose Warner, but had yet to gather any significant support on the committee. "We just announced that any candidate who wanted a briefing could get one," said Obenshain campaign spokesman Richard Lobb. "Warner and Miller were the ones who showed up."

Warner was accompanied on his trip to the governor's office by former 10th congressional District Rep. Joel T. Broyhill, his preconvention campaign manager, and Dr. James M. Helms Jr., 5th congressional District Republican chairman.

Helms, a member of the GOP State Central Committee and a strong Warner supporter, said, "It mystifies me they (the committee) would be considering anyone else." He said Warner and Obenshain held similar positions on all the major campaign issues and Warner had been a tireless worker on Obenshain's behalf since the convention.

In New York, meanwhile, Elizabeth Taylor Warner's press agent, John Springer, said the couple had learned of Obenshain's death while en route from a GOP fund-raiser in New Hampshire to a theatrical opening by entertainer Sammy Davis Jr. in New York.

He said the Warners had planned to leave within the next two weeks for "an extended European holiday" in Ireland, England, France and "her home in Switzerland" and would have been away several months.

He described the actress as "quite shaken" by Obenshain's death. "She identified with Mrs. Obenshain, having lost a husband herself in a plane crash," he said. Film producer Michael Todd, Mrs. Warner's third husband, died in a crash in 1958.

Springer said the vacation plans are still pending but the couple canceled all other engagements after Obenshain's death. "They're not even thinking of anything political at this time," he said.