MACKINAC ISLAND, MICH. -- The biennial gathering by Michigan Republicans at this scenic resort ran amok last weekend with a threatened walkout, a pushing incident and general rage and hatred because George Bush has all but lost Round One of the fight for the presidential nomination.

The vice president could be humiliated, finishing a poor third when Michigan's 77 delegates next January become the first selected in the nation. His main hope is to break up the right-wing coalition between supporters of television evangelist Pat Robertson and Rep. Jack Kemp. That effort intensified Bush malevolence here against fundamentalist Christians, who have entered the party for the express purpose of backing Robertson.

At the end of a rancorous weekend, the coalition-busters had failed. Kemp himself was called in to reassure supporters grown uneasy about embracing Robertson. Coalition strategists target more than 40 Robertson delegates, about 25 for Kemp and nine or 10 for Bush. That would wound the vice president eight days before Iowa's caucuses.

Contempt for the Robertson newcomers is genuine. The Michigan party, which has not elected a new candidate to major statewide office in 25 years, had been comfortable if not successful. Unexpected hordes from Robertson's Freedom Council who transformed the 1986 primary were viewed not as replenishment for a desiccated party but as a barbarian invasion. Bush delegate candidates still complained here about losing to newly minted Republicans.

Bush managers must convince Kemp adversaries -- pals in the tight little world of the Michigan GOP -- that the religious right is the enemy. Although junior partners in the right-wing coalition, some Kemp backers do view Robertson's Christians with the same trepidation as Bush regulars.

Robertson phobia was the reason party stalwart Susan Chmiewleski gave for switching from Kemp to Sen. Robert J. Dole (a latecomer in Michigan). A bigger threat to the coalition was the potential defection of Larrain Thomas, Michigan party vice chairman and Kemp's state cochairman.

''I am truly disturbed, and so are others,'' she told us as the conference began. What bothered her was a State Central Committee vote in which the Kemp-Robertson coalition beat down Bush's effort to make 1,200 officeholders and nominees state convention delegates without their being elected. She suggested the coalition should break up, even if that hands Bush the state. If Kemp would not agree, would she quit his campaign? ''I'd have to think about that,'' she replied.

Nine hours later, after Kemp had delivered a stem-winder to the conference, Thomas was all smiles. Kemp had publicly expressed support for keeping her ally, E. Spencer Abraham, as state chairman after Robertson proposed he be sacked. In a private meeting, Kemp had addressed her misgivings. ''I really feel good about everything,'' she told us.

Robertson himself did not make coalition building easier. He arrived here declaring that Peter Secchia, tough-talking Grand Rapids multimillionaire and fervent Bushite, must go as Republican national committeeman next January. Then, for good measure, he added that Abraham -- neutral for president but with Bush in favoring the nonelected delegates -- should be sacked as well.

Once Robertson proposed his purge, Bush forces went all out to stir up Republicans attending here -- mostly Bush backers willing to put down $440 per couple for two nights at the Grand Hotel. On Sunday morning, every conference participant found on his hotel doorknob a package containing a chocolate bar in the likeness of George and Barbara Bush and a letter indicting Robertson's conduct as ''appalling.''

The night before, Bush backers planned a walkout when Robertson rose to talk. Neil Bush, representing his father (happily away from this maelstrom, in Detroit meeting the pope), called it off. Even so, a particularly robust Kemp speech was followed by an uncharacteristically laid-back Robertson performance to hostile listeners. He left the dining room commenting about a ''stiff'' crowd.

Before dinner, Robertson was confronted by state Sen. Doug Cruce, who blocked his way. Cruce described himself as one of the state officeholders ''disenfranchised'' by Robertson's rules of order and demanded what he would do about it. When national campaign manager Mark Nuttle tried to pull Cruce away, the pro-Bush legislator shouted, ''Take your hands off me.''

Nuttle then floated vague offers of compromise, but everybody knew there would be none. The intricate Michigan process, long ago designed to boost George Bush early, by unexpectedly attracting thousands of new Republicans promises an early humiliation for the vice president's campaign unless the courts come to his rescue.