State Republicans threw a big convention-rally here this weekend, and the novelty was that none of the presidential candidates came.

Nor were they invited. Nor, it turned out, did their absence seem to make any difference.

The battle for the 1988 GOP nomination raged on quite nicely, thank you, without them. Forget what the calendar says. In Michigan it already is 1988, and the GOP presidential organizations here are so geared up that the flesh-and-blood of a candidate is almost a distraction.

Vice President Bush's political action committee has a paid staff of 13 in Michigan (four full-time and nine part-time). They were identifiable this weekend not just by buttons, pins and literature, but by tie clips showing a replica of the World War II plane that Bush, as a young Navy pilot, was shot down in over the Pacific. (The vice president, subject of recent columns by George Will and Mike Royko alleging he is a "lap dog," has been playing up his war record in recent speeches, too.)

Rep. Jack Kemp's (R-N.Y.) Michigan Opportunity Society, which has eight full- and part-time staffers in the state, handed out glossy brochures all weekend encouraging party activists to run for precinct delegate and saw to it that reprints of articles critical of Bush were well circulated among the 1,500 party workers who gathered here.

The political action committee of Senate Majority Leader Robert J. Dole (R-Kan.) sent out two operatives from Washington and, like the others, hosted a hospitality suite. The Rev. Pat Roberton's Freedom Council, which has a staff of seven organizing fundamentalist Christians in the state, was also working the conventioneers.

"There is already such a fever pitch of involvement," said Saul Anuzis of Lansing, who was state youth chairman for Bush in 1980, but who is now backing Kemp. "Hard to believe it is only 1986," he said.

Michigan Republicans invited this early activity when they became the only state party in the country that chose to hold its first event of the 1988 delegate-selection process this summer.

On Aug. 5, an estimated 10,000 precinct delegates will be elected by Michigan GOP primary voters. They will serve in that party post for two years. More importantly, they will become the universe of electors who, at a date yet to be determined in early 1988, will caucus to choose county delegates, who in turn will choose state delegates, who in turn will choose Michigan's delegates to the national convention. So the name of the game has been to recruit candidates for these delegate slots -- less than half of which are expected to have incumbents seeking relection in August.

At the moment, it is pretty much a two-man shootout between Bush and Kemp. (Dole has held off from authorizing a paid staff operation here, and Robertson's Freedom Council is expected to compete for delegates only in scattered areas.)

Bush enjoys here what he has almost everywhere, the vast bulk of the party leadership. Three months ago, his PAC unveiled a 686-person state steering committee. It has since doubled in size.

His PAC, the Fund for America's Future, has budgeted $100,000 to spend in the state through June, with more presumably to follow later. Technically, though, the PAC is not supposed to advance the fortunes of a presidential candidate; it supposed to give money to candidates for federal office or engage in party building.

The PAC's lawyers, anticipating a potential legal problem, have asked the Federal Election Commission to spell out how it can and cannot spend their money in Michigan; an advisory opinion is expected within a few months.

The other Bush burden here is the familiar bugaboo of expectations. "We have to do more than win here, we need to win with a margin," said L. Brooks Patterson, another Bush state cochair. He said his is was to have a solid majority of delegates in 14 of the state's 18 congressional districts.

Though the state GOP leadership asked Bush and Kemp not to come this weekend so it could keep the rally focused on the gubernatorial race, they couldn't resist bringing in two national "stars" -- former U.N. ambassador Jeane J. Kirkpatrick and former secretary of state Alexander M. Haig Jr.

Haig said that "at the appropriate time" he might throw his own hat in the ring but argued that it was "diversion" to get too involved in presidential politics in 1986.

This weekend in Kalamazoo, his was a lonely voice.