DETROIT -- Vice President George Bush's dogged managers have averted what once seemed sure defeat in Michigan and severely wounded his opponents here. But they will leave a battlefield littered with Republican dead.

That this weekend's state party convention in Grand Rapids will give Bush 35 of the first 77 delegates selected for the Republican National Convention is only part of the significant victory for the vice president. Pat Robertson's thrust has been blunted, his right-wing coalition with Rep. Jack Kemp destroyed and Kemp's own forces divided.

Yet, regular Republicans who lead Bush forces here sigh in relief rather than cheer in victory. The real story of Michigan is that the transplant of Christian evangelicals was rejected by the GOP body politic. The message from two confused years here does not bode well for the party's growth.

The bitterness of Robertson's newcomers is intensified by their conviction that victory was stolen from them. A combination of state court decisions and the defection of a mere 70 Kemp state convention delegates (out of 1,805) who wanted to coalesce with Bush rather than Robertson gives the vice president his margin in the state convention. The last doubt was removed when Bush outorganized Robertson at county conventions two weeks ago.

That fait accompli posed one remaining question: Shall Kemp accept the Bush offer of 30 conventiondelegates (leaving 12 for Robertson), or join the religious broadcaster's forces in a ''rump'' state convention, sending a rival delegation to New Orleans?

Kemp's answer is that, while professing loyalty to the coalition with Robertson, he cannot disregard court orders and join the rump. Besides, if he is getting 30 delegates, he wants to pick his own people.

David Walters, Robertson's state campaign director, contends Kemp national campaign manager Charles Black has sold out the coalition ''under the guise'' of legalities and that Kemp's grass-roots backers agree. Indeed, Kemp's forces here not only are smaller than Bush's and Robertson's but are sharply split.

State Sen. Richard Posthumous, Kemp's co-chairman who defied his candidate by leading those 70 delegates out of the coalition, is condemned privately by campaign leaders. W. Clark Durant, a Detroit conservative activist who last weekend was speaking as Kemp's surrogate in Arkansas, told us, ''I wouldn't serve on the delegation. I just can't.'' But he added he would if Kemp requested it, and the campaign's national managers predicted he will be a delegate.

The divisiveness spreads to Kemp's high command. David Hoppe, the congressman's chief of staff, has fought Charles Black's Michigan strategy on grounds it will sufficiently alienate Robertson to kill hopes for his support at New Orleans. Kemp campaign leaders claim Hoppe reflects New Right operative Paul Weyrich, who has ties with Sen. Robert Dole as well as Kemp.

Although Dole is a noncombatant in Michigan, operative Don Devine has been here for the senator trying to keep the conservative coalition alive to prevent a clear Bush win eight days before the Iowa caucuses. Robertson's strategists contend an ''unclouded'' Bush triumph in Michigan would give the vice president 10 added percentage points in Iowa, and Walters intends to cloud the result with a rump convention.

But Kemp's decision to accept 30 delegates was not the beginning of trouble with Robertson. The two wings of the conservative coalition were uneasy with each other, many Kemp activists feeling closer culturally to Bush partisans. Dick Minard, Kemp's state campaign manager, did not hide distaste for Robertson national campaign manager Marc Nuttle. Robertson's private repetition of negative personal comments about Kemp was resented by the congressman's operatives.

That does not match Bush-Robertson animosity. Oakland County Prosecutor Brooks Patterson, a Bush leader, first welcomed the evangelicals as well-intentioned conservatives sharing his views on capital punishment. Now he prays that after the state convention, Robertson's warriors will return to their churches. The probability that many will not do so suggests that the victory of the Bush forces may be as short-lived as it is narrow and costly.