WHAT IS TO come of Puerto Rico? There it sits in the Caribbean, an American "commonwealth" twice as poor as the poorest state, peopled by second-class American citizens (no federal taxation but no federal representation either), an accidental colonial acquisition often given to regarding itself as a colony still: a "state" of discontent. Puerto Ricans agree things must change, but they cannot agree on whether to abandon the existing imperfect model of commonwealth for another model (which?), for statehood or for independence. And they despair of enlisting the 50 states to become partners in a quest for change.

For a while it looked as though Puerto Rico would use its vote on Nov. 6 to try to crash the barrier of American inattention. The island has had a rough passage dealing with a recession aggravated by four years of Reagan budget cuts, and Gov. Carlos Romero Barcelo, looking for a villain, found one in commonwealth and ran for reelection on a pledge to force the statehood issue. His victory could have severely embarrassed the administration, which, like its predecessors, nods to Puerto Rican self-determination but is entirely unprepared to deliver a graceful positive answer to any bid to become the 51st state.

In the event, Gov. Romero was edged out by former governor Rafael Hernandez Colon. A commonwealth regular, Gov.-elect Hernandez promises to "strengthen and reinvigorate" commonwealth. But he is clearly more interested in cooling down the status quarrel and doing what can be done to revive the island's gasping economy.

This is the best course. The status debate divides Puerto Ricans along commonwealth and statehood lines, with independence perennially a remote third. It tempts the island's political class to expend itself on a matter nowhere near ripe for resolution either in Washington or in San Juan. Some sort of formal, continuing mutual inquiry into matters of status would be extremely useful. No less urgent, however, are joint approaches to Puerto Rico's economic and social calamities.

Puerto Rico needs an investment strategy tailored to the fact that it has not a low-wage labor force but the most skilled labor force in the Caribbean. It also needs assurances that broad American policy changes undertaken for reasons unrelated to Puerto Rico do not undercut the island -- as Mr. Reagan's Caribbean Basin Initiative, for instance, at a stroke ended Puerto Rico's favored access to the mainland market.

None of these important choices will be made even halfway right, however, unless the American government -- Congress included -- pays closer attention to the island's sensibilities and needs.