Why can't Massachusetts Republicans get their act together?

ALL the winners at this month's Massachusetts Republican state convention were not there. While there is nothing to suggest that Gov. Michael S. Dukakis or the Democratic Party had a finger in the GOP proceedings, the Bay State chief executive may have benefited from what happened.

The wrangling within the GOP leadership, so evident at the Worcester gathering, has left that party badly split and has perhaps disillusioned many party newcomers. The GOP makes up scarcely 13 percent of the state electorate. Its leaders should be rallying around the party for a tough campaign and seeking unity, not pushing their own agendas.

The failure of Gregory S. Hyatt to win the nomination for governor had to disappoint him and his supporters, including Raymond Shamie, the party's 1982 and '84 nominee for the US Senate. But it's questionable whether Mr. Hyatt would be as strong a contender for the governorship as state Rep. Royall H. Switzler, who won endorsement.

Mr. Hyatt's candidacy was not helped by allegations that he had mishandled a 1985 signature drive for a petition, backed by the Associated Building Contractors.

It might be noted, however, that dissatisfaction with his performance surfaced long before the convention, and some GOP activists were already shopping for a candidate to challenge Governor Dukakis.

Yet the draft-Switzler movement would not have gotten off the ground at the 11th hour, if many prominent party members had not viewed Hyatt as too hard to sell.

Some delegates may have felt that Mr. Hyatt is too young or too inexperienced. Unlike Mr. Switzler, who has been an articulate voice on Beacon Hill for more than a decade, Hyatt has never held elective office.

Switzler supporters included a cross section of party conservatives and moderates. Many are state lawmakers, familiar with Switzler's debating skills and knowledge of state government. Even his staunchest political critics concede that he does his homework. If he wins the nomination in September, the sixth-term legislator from Wellesley seems sure to be a tough Dukakis foe.

Obviously embittered by his loss to a last-minute opponent, Hyatt may come to regret the poor-loser image he projected at the convention. If he pursues the nomination in the primary, which he seems determined to do, neither he nor his supporters can afford to attack Switzler too hard, lest they weaken GOP prospects for unseating Dukakis.

Hyatt, a conservative with populist leanings, is a former director of Citizens for Limited Taxation and was a backer of Proposition 2. In 1984 he ran for the state's Fifth US Congressional District, and last fall was in the forefront of a petition drive opposing the mandatory wearing of auto seat belts.

That question will be on the November ballot, something Hyatt had been hoping to take advantage of in a campaign against Dukakis, who sponsored the seat-belt law. Switzler voted for and supported the statute, which he maintains promotes public safety.

On most other gubernatorial campaign issues there is little or no disagreement between Switzler and Hyatt.

Besides Mr. Shamie, the millionaire industrialist bent on reshaping the Bay State GOP along more conservative lines, the Hyatt loss dealt a setback to former GOP state chairman Gordon Nelson, Hyatt's campaign manager.

And the Shamie-Nelson forces suffered another setback with the endorsement of state Rep. Andrew S. Natsios for state auditor. He bested House minority leader William G. Robinson of Melrose by more than 4 to 3. The two are expected to square off in September.

The convention also endorsed Nicholas Nikitas of Boston for lieutenant governor, Deborah Cochran of Dedham for secretary of state, Edward F. Harrington of Needham for attorney general, and L. Joyce Hampers of Weston for state treasurer.