No longer are Congress, specifically the Democratic House, and President Reagan at odds on Nicaragua. The American political system has worked over the issue and finally fetched up at an agreed policy. In its central feature, it permits, after a year's lapse, the resumption of direct aid to the Nicaraguan contras. No fewer than 73 Democrats voted for it, reversing their party's previous veto on aid and giving the president what he is pleased to call an important victory.

There is always potential value in establishing a bipartisan approach to contentious foreign policy questions. The very process of establishing bipartisanship can be, if bloody, a positive influence on policy. Certainly it was that way as Congress and the president gradually came together on El Salvador in 1983-84. Congress added its emphasis on human rights, democratization, reform and political dialogue to Mr. Reagan's stress on the military struggle. The outcome was a balanced policy that has a reasonable chance of working over time.

It has yet to be shown, however, that the same process of establishing bipartisanship can have a similar positive impact in Nicaragua. There the two sides' contributions, rather than reinforcing each other, may tend to cancel each other out.

From the House Mr. Reagan won a resumption of aid to the contras, but under conditions (logistical aid only, outside CIA/Pentagon channels) that make supporters uncertain whether -- unless the terms are sweetened in conference with the Republican Senate -- the aid will produce the military pressures essential to success.

The conditions also include a statement from Mr. Reagan that he seeks not to overthrow the Sandinistas but to coax them into negotiations and new elections. Whether this latest avowal of administration purpose describes its actual intent or represents any real change is very much up in the air. So is the question of whether this new assertion will limber up the Sandinistas and make them readier for compromise. The Sandinistas can hear elated insurgents saying that the aid vote has restored an American seal of unequivocal approval and given them the boost they need to press on.

The possibility exists that the United States may end up with something of the worst of both worlds: certainly not enough conciliation and possibly not enough pressure to make the Sandinistas alter course. The war could grind on, producing additional losses, sidetracking diplomacy and increasing the chance of American involvement as frustration mounts.

But the debate, for the time being, is over. The question is whether the compromise can work.