THE VEXING Puerto Rico statehood issue seems about to sink below the horizon of mainland consciousness for at least another four years. This follows from the gubernatorial election. It will take a recount to determine whether the candidate favoring statehood or the one demanding improvement of the existing "commonwealth" won. But it is already clear that, with the Independence Party taking 7 percent of the vote, neither major candidate got the majority that was the minimum necessary to begin convincing the 50 states to contemplate a change. President-elect Ronald Reagan had expressed support for statehood but with the demanding but fair condition that a "great majority" of Puerto Ricans embrace it "with passion." Incumbent Gov. Carlos Romero Barcelo had no choice but to say, after the election, that his scant victory with a plurality, even if upheld, would not permit him to call a plebiscite to advance statehood, as he had hoped to do next year.

For most mainland Americans, this is probably just as well. The public had only begun to be seized of the issue of creating a 51st state, but it has been recognized to be surpassingly difficult. It would require a decision, if asked by Puerto Rico, to make good on an oft-given pledge to grant statehood to a group of now-second-class Americans of a differing cultural orientation and a decidedly lower economic level. The world, especially the Latin part of it, would have kept a beady eye on how the United States treated this odd colonial inheritance, picked up casually in the Spanish-American War and treated all too casually since.

For Puerto Ricans, however, the passions surrounding the status question may mean that the no-decision verdict of the gubernatorial race translates into corrosive stalemate. Commonwealthers have cause for relief that the statehood drive has been sidetracked, but statehooders are in a position to block progress to improve the terms of commonwealth.

It will hardly suffice for the Reagan administration to take the prim do-nothing position of waiting for a Puerto Rican consensus. It must work within the existing commonwealth framework to better the administration of the big transfer programs (food stamps) on which most Puerto Ricans depend and to spur local development if it can. To do this, it should remedy a glaring and long-recognized structural flaw and create a single office to be a Puerto Rican focal point within the executive branch -- and to integrate treatment of Puerto Rico with the general policy line. The status debate can be put into low gear, but the status quo needs to be changed.