With the Salvadoran election over, the Reagan administration can be expected to come under mounting pressure to find a negotiated solution to the revolutionary turmoil in Central America.
Up to now there has been little sign that any of the protagonists were yet ready to abandon their strongly held positions.
Washington sees as the key factor the attitude of Nicaragua and Cuba toward El Salvador. Months ago it laid down as an essential condition for warmer relations with Nicaragua an end to that country's support of the Salvadoran insurgency, especially the supply of arms through Nicaraguan territory (presumably from Cuba).
Reagan administration officials made it plain that they were determined that nothing should interfere with the March 28 vote in El Salvador. Nor, when that was over, would they accept what Secretary of State Alexander M. Haig Jr. called last week ''a negotiated distribution of power over the heads of the people of El Salvador.''
Nonetheless, even before the Salvadorans went to the polls, the reports had begun to pour in of contacts between the various parties.
Gen. Vernon Walters, it was leaked, had acted as a secret US emissary to Cuba in early March. Mexican Foreign Minister Jorge Castaneda had shuttled very visibly between Washington, Nicaragua, and Cuba.
At the United Nations, Nicaraguan leader Daniel Ortega Saavedra hit out at the US March 25, but said his country and Cuba were ready to negotiate unconditionally. And Assistant Secretary of State Thomas O. Enders was said to be considering a meeting with a senior Nicaraguan official in Mexico City. Mexico, in fact, announced March 26 that a meeting would take place in April.
But no sooner had the word gotten out when the State Department denied that any such talks were set.
Despite all the maneuvering, it is by no means clear either that the Cubans and Nicaraguans are ready to drop their backing for Central American insurgencies, or that the Reagan administration is prepared to talk about anything else.
Certainly, US officials have not been prepared to make substantive moves before the Salvadorans have had an opportunity to express their views at the polls -- or by failing (either through intimidation or conviction) to go to the polls as the leftist insurgents would have preferred. Meanwhile, administration officials, from Secretary Haig downward, have poured cold water on the possibility that negotiations could provide a way out of the present impasse. And they have continued to excoriate Central America's revolutionary leftists.
There is no doubt about the overall aim of the administration. It is to prevent Central America from becoming communist -- an aim in which most Americans and Western Europeans would concur. The question arises over how to prevent it.
And in this the administration finds itself caught between conflicting pressures. Two of them are domestic:
* The Reagan administration's doctrine of global containment of the Soviet Union. This theory, popular on the American right, calls for a vigorous US reaction to any situation threatening US interests, no matter where, on the assumption that the Soviet Union or its proxies (such as Cuba) must be behind it. This is how supporters of the doctrine perceive the current upheavals in Central America.
* The mounting opposition to American military support to Central America, particularly to El Salvador. This opposition started at grass-level and gained unexpected backing from the Roman Catholic Church. It is now making itself felt in Congress. It was also exemplified by Saturday's demonstration in Washington when some 20,000 people turned out to protest US policy in El Salvador. The Vietnam experience is not forgotten.
Other pressures come from outside the US:
* The US failure to change the situation in Central America, especially in El Salvador, after 14 months of military and economic assistance.
* Mexico's persistant and activist inititives. Mindful of its own pre-World War I revolutionary experience, Mexico favors political rather than military solutions for Central America. Washington is taking Mexico of the 1980s more seriously partly because of Mexico's oil wealth and the effect of its burgeoning population on the US.
* A lack of enthusiasm on the part of US allies for what is perceived as an escalating militancy in US policy toward Central America.
It is hard to dispute the strategic importance to the US of the seven small republics of the Central American isthmus - Panama, Costa Rica, Nicaragua, El Salvador, Honduras, Belize, and Guatemala. Geography puts them within a natural US sphere of influence. And from them, singly or collectively in hostile hands, can be mounted a threat to the eastern approach lanes to the Panama Canal, a vital maritime route.
US policy has been directed toward keeping them out of hostile and above all communist hands. For half a century and more, that imperative has led Washington to support repressive, right-wing, and usually military regimes in Central America -- provided those regimes toed the US line.
This in turn has produced revolutionary situations in Central America under pressure-cooker conditions.
Mexico and others argue that US military intervention against revolutionary movements is most likely to be counterproductive, driving Central American countries closer to the Soviet Union and Cuba. Given recent history, say the Mexicans, these revolutions are both inevitable and indigenous, even if the Russians and Cubans move in to back them.
The wiser alternative for the US, according to the Mexican argument, is to negotiate with the revolutionary left, to ensure it remains as indigenous as possible.
Some in the Reagan administration have countered that the US is against conceding at the negotiating table what the revolutionaries know they cannot win at the ballot-box and are therefore trying to win with guns.