LANSING, MICH., DEC. 12 -- The fragile Michigan alliance between Marion G. (Pat) Robertson and Rep. Jack Kemp (R-N.Y.) barely staved off a challenge by Vice President Bush's supporters today in a vote on party rules that virtually assures that the selection of this state's 77 GOP presidential delegates will continue to degenerate into a battle of lawsuits and competing rump conventions.

The 52-to-48 Republican Central Committee vote prevented what probably would have been a fatal blow to the Robertson-Kemp conservative alliance -- almost guaranteeing a Bush victory in Michigan, the first state to select national convention delegates.

The vote does not, however, as-sure any of the competitors a firm edge in the struggle for Michigan's delegates.

Instead, any campaign facing the prospect of defeat has the option of adopting "scorched-earth" strategies designed to muddy the contest so much that it would be nearly impossible to determine a winner. Tactics could include legal fights and competing state conventions to choose different sets of delegates to send to the GOP convention in New Orleans.

The tight vote by the Republican Central Committee was immediately denounced in an emotional floor speech by former governor -- and Bush supporter -- George Romney.

"You have self-destructed today," said Romney, who led a resurgence of the Republican Party in Michigan 25 years ago. "You can kiss good-bye to Republican victories in 1988 in Michigan."

Romney charged that the vote was a repudiation of an agreement signed by key principles in the Robertson, Kemp and Bush campaigns earlier this year, and that the resulting hostilities within the state GOP will prevent the party from defeating Sen. Donald W. Reigle Jr. (D-Mich.) and from taking control of the state House.

The vote was praised by members of the coalition of evangelicals, antiabortion and new-right leaders making up the Kemp-Robertson alliance.

"The evangelicals who first came up in 1976 and 1980," said David Walters, head of the Robertson campaign in Michigan, "they have learned how to play hardball. This excites me."

Dick Minard, Kemp's Michigan manager, declared the vote a repudiation of "a desperate attempt by the Bush campaign to salvage a failing campaign."

Harry Verayser, chairman of Robertson's campaign, contended the vote will be a signal to evangelical and conservative Roman Catholic voters that they are welcome to participate in the GOP. "If we close the door on them, we close the door on the only reservoir of voters available to the Republican Party," he said.

At a GOP meeting in Grand Rapids Jan. 29-30, Michigan is to become the first state to select delegates to the national convention. Until last Monday, it appeared that Robertson had a strong chance of winning a plurality of the delegates, and Bush was headed for an embarrassing last-place finish in a state where he won the 1980 presidential primary against Reagan.

On Monday, however, a number of key leaders of Kemp's Michigan campaign jumped ship to join forces with the Bush campaign in a deal guaranteeing Bush a plurality of delegates and Kemp second place. The vote today was a blow to that deal, but does not guarantee its failure.

The Kemp defectors were disavowed by Kemp himself, who came into the state on Thursday to reorganize the leadership of his campaign and to reaffirm his loyalty to the anti-Bush alliance of Robertson and Kemp supporters. Minard argued that even though the Bush campaign might be able to offer more delgates to Kemp, the first priority is to defeat Bush in Michigan to show that a frontrunner can be wounded in an early state.

The vote taken yesterday was to change party rules to prevent county Republican executive committees from setting up rules governing the selection of delegates to the state convention that would favor Bush. While seemingly an arcane issue, the county apportionment plans have the potential to determine who wins in Michigan.

"As someone who works in it {the presidential fight} day to day, it just plain stinks," said Paul Welday, deputy Kemp manager.

Throughout the past week, charges of vote-buying, job offers, firings and threats have flown back and forth as the competing camps have sought to win the vote today. Bush supporters have acknowledged offering political and financial help to Kemp supporters who plan to run for local office, and assuring at least one Kemp staffer that he would have a job if he cast his vote with the Bush forces today.

The splintering of the Kemp forces has turned Michigan into a highly competitive contest. In August 1986, 9,000 precinct delegates were elected. They will ultimately select Michigan's 77 convention delegates. Roughly 45 percent backed Bush and 45 percent backed Robertson; the remaining 10 percent supported Kemp. The Kemp split means the race is wide open.