AFTER A YEAR in which popular revolutions of the left toppled American-supported martial-law regimes of the right in Iran and Nicaragua, it is only prudent for Americans to be checking the roster of friends and allies for other positions in which the United States may be exposed. Any such review brings you quickly to the Philippines, where President Marcos is nearing the end of a decade of military rule and where assorted kinds of opposition -- church and secular, political and military, lower-class and middle-class, Marxist and Moslem -- are bubbling up all around.

Regrettably, very little of this sentiment was allowed to be expressed in the local elections (the first in eight years) that Mr. Marcos staged over the weekend. It was not simply that his candidates, using the formidable advantages his rules ensured them, swept most contests. Mr. Marcos also failed to persuade the principal opposition parties that is was worth their while to compete at all. Simultaneously, he launched a dialogue on "political normalization" with his long-jailed chief political rival, Benigno Aquino, whom he even freed for three weeks to conduct his own political soundings. But neither the elections nor the normalization gambit, which most Filipinos seem to have dismissed as a snare though it has not yet been played out completely, indicate any more than a slight and tentative readiness on Mr. Marcos' part to try to defuse the popular explosion that almost all experts believe is otherwise a near certainty.

The United States, by the military-bases agreement it made a year ago, accepted a ceertain obligation not to hassle the Marcos regime, in public anyway, for its perceived internal failings. Bases aside, President Marcos has earned further American gratitude and discretion by offering major help in receiving boat people and by voting right in the Security Council on Afghanistan -- things like that. American officials can see that the Filipino opposition is building and that it tends to hold Washington responsible for the government's undemocratic ways. Yet they view the problem less as hedging against a possible future disaster than as balancing out a set of competing interests now.

In the current calculus, the emphasis of American policy is inevitably on ensuring continued security cooperation and demonstrating the benefits and reliability of the American connection. We don't quarrel with this emphasis. But we would like to hear the administration explain, perhaps in the testimony it is about to offer the House, what it is doing to ensure against a backlash some day from Mr. Marcos' domestic foes. The Philippines, unfortunately, is not the only place of which that question must be asked.