Former Navy secretary John W. Warner was nominated for the U.S. Senate yesterday by a Virginia Republican Party united by grief and its hopes for November.

In an extraordinary session lasting less than a hour, the party's state central committee chose Warner by acclamation to succeed former nominee Richard D. Obenshain, who was killed Aug. 2 in the crash of a light plane near here.

Warner, 51-year-old sixth husband of actress Elizabeth Taylor, narrowly lost to Obenshain June 3 in a lengthy and tumultuous state GOP convention. He will oppose Democrat Andrew P. Miller, a former state attorney general, in the general election.

The committee's action capped an unprecedented 10-day struggle within the state party as Obenshain's supporters sought to reconcile loyalty to their late standard-bearer's conservative principles with the personal flamboyance and largely untested political philosophy of Warner and his actress wife.

Warner, a wealthy Northern Virginia landowner, burst on the state political scene two years ago after his marriage to Taylor. Last year the Warners raised thousands for the party by appearing around the state.

Until then, it Virginia at least. Warner was a virtual unknown, and to many in the state GOP he remains that today.

Warner sought to reassure the remaining skeptics yesterday in his acceptance speech, declaring that "I am your candidate and belong equally to each and every one of you . . . Dick Obenshain was a man of principle. John Warner is a man of principle."

Miller immediately attacked Warner in a news conference, citing Warner's ties to Washington. "We need a senator who is not part of the Washington establishment, but one who stands on his own two feet," Miller said.

Obenshain's widow, Helen, in an emotional appearances before the Republican committee, sounded a further unity note by declaring her intention to "help John in every way I can" during the upcoming campaign.

But she cautioned both him and the assembled delegates to remember that the state party Obenshain helped bring to dominance in Virginia was built on the principles of "limited government and individual freedom. Please don't ever compromise those principles," she said.

In a state where predictability is a valued asset and political longevity highly prized, Warner's candidacy marks a further shift toward new, moneyed candidates with media flair.

Like Democratic Lt. Gov. Charles Robb - who even his supporters describe as having "parachuted in here" - Warner and his closest supporters have provided a challenge to Virginia's political establishment that some longtime leaders in the state find disturbing. But Warner strategists have pointed out repeatedly that Robb, a son-in-law of the late president Lyndon B. Johnson, was able to capture many new votes to his party and Warner they say can do the same.

In his nomination speech for the former Navy Secretary, Virginia Gov. John N. Dalton noted yesterday that the party's nominee "must be a man that others outside our party can support . . . We need the help of others outside the regular Republican Party."

Invoking the names of Sen. Harry F. Byrd Jr. (I-Va.) and conservative Democratic Rep. W.C. (Dan) Daniel of Danville and David E. Satterfield III of Richmond, Warner said, "I pledge to you that my philosophy and my actions as your next U.S. senator will be consistent with the distinguished record and precedent set by your congressional delegation . . . In times of great decision I draw upon a quotation that is familiar to each of you: 'To thine own self be true.'"

The nomination meeting produced an outpouring of unity with spokesmen by every faction of the state party coming forward to second Warner's nomination. An Obenshain staffer said privately, however, that the unity was far more tenuous than it appeared. And many staffers were holding their breath until all the speeches were over. "This was a very, very fragile thing," one Obenshain aide said.

Much of it, including Helen Obenshain's speech, had been worked out within the past few days. The most significant factor, the staffer said, was the movement to make Warner's nomination one by acclamation.

The motion was made by Jade West of Arlington, a representative of the Young Republican Federation of Virginia, and one of Obenshain's most devoted and conservative supporters. Only a few days ago she had been quoted as declaring "We're Obenshain people and we'll always be just Obenshain people."

Her change of heart, however, was only the most recent in an extraordinary political year in the state that has produced a Senate campaign that virtually no one evisioned little more than a year ago.

Miller said later he expected some of the Obenshain supporters to back his campaign. ". . . I feel confident that as the people of Virginia learn more about John Warner and his positions on the issues, they will turn to me," Miller said.

EOP spokesman Richard Lobb said he expected it would be 10 days to two weeks before Warner could get past the routine staffing and fund-raising necessities of fielding the new campaign to start making public appearances.

He said Warner expects to keep on most of the existing Obenshain staff and will honor whatever public appearances on the existing Obenshain schedule are mutually agreed upon.

But he said some in the party have counseled Warner not even to begin campaigning until October, and the candidate himself hinted a short campaign may be in order. "Everybody knows that people get bored when political campaigns get too long," Warner said in his acceptance speech. "We're not going to bore them."00