A consensus seems to be developing in the US Congress which would allow President Reagan to get the new military aid for El Salvador which he is seeking. But he may have to pay a price for it: new strings attached to the aid.
Some senators and congressmen are insisting that a stronger effort be made to negotiate an end to the Salvadorean war. Under one draft bill now being considered on Capitol Hill, if a stronger effort is not made, further military aid would be restricted or converted into economic and humanitarian aid.
In oversimplified terms, the trade-off would be more money in return for peace negotiations. This solution is favored in particular by congressional liberals.
Some senators and congressmen argue, however, that the President will be able to secure the aid he wants merely by vigorously reaffirming the administration's commitment to conditions that have already been attached to the aid. House majority leader Jim Wright (D) of Texas seems to fall into this category.
Mr. Reagan is already required to certify periodically to the Congress that the Salvadorean government is, among other things, making a concerted effort to comply with internationally recognized standards of human rights and is demonstrating good-faith efforts to begin talks with all major factions in El Salvador which have declared their willingness to find an equitable solution to the conflict.
In light of what some observers consider to be a deterioration in the Salvadorean government's position on the battlefield, President Reagan wants an increase of $60 million in military aid for El Salvador. He is also thinking of increasing the number of American military trainers working with the Salvadorean armed forces beyond the limit of 55 which the administration had set for itself earlier. Reagan is expected to make formal proposals on these matters by the end of this week.
As part of his continuing campaign to get more aid for El Salvador, the President met at the White House on Tuesday with 22 congressional leaders. Charles H. Percy, the Illinois Republican who is chairman of the Senate Foreign Relations Committee, and Clement J. Zablocki, the Wisconsin Democrat who heads the House Foreign Affairs Committee, said after the meeting that the administration was likely to get the extra money for El Salvador if conditions were attached.
Among the conditions, said Senator Percy, there must be: an amnesty program for guerrillas now fighting the government; protection for opponents of the Salvadorean government before, during, and after elections; and a ''serious conversation'' with the opposition, such as Pope John Paul II has called for.
As explained by Percy, however, this conversation would be mainly aimed at bringing the guerrillas into the existing elections process in El Salvador and not at getting them a share of political power. The conditions set by the senator were thus not greatly different from those which have already been set by the Congress or stated as goals by the administration. The administration has advocated an amnesty program and protection for opposition participants in elections.
Regardless of the outcome of the renewed debate over conditions for aid to El Salvador, some observers think that the pressure on the administration to move toward a negotiated settlement of the Salvadorean conflict has increased by a degree or two. In some congressional offices, letters from constituents are running heavily against increased military aid for El Salvador. In congressional testimony, the US Catholic Bishops Conference has just reiterated its strong support for a ''dialogue, cease-fire, and negotiations.''
Administration spokesmen seemed to lose points in the debate over El Salvador recently when they accused Roman Catholic priests of cooperating with the Salvadorean guerrillas. Appearing before a Senate subcommittee, Secretary of State George Shultz criticized ''churchmen who want to see Soviet influence in El Salvador improved.'' In a meeting with Latin American experts, Vice-President George Bush expressed puzzlement over priests whom he accused of working with Marxist revolutionaries.
The remarks by Mr. Shultz and Mr. Bush upset a number of senators and congressmen. Sen. Dave Durenberger (R) of Minnesota was so infuriated by their remarks that he fired off a four-page letter on El Salvador to President Reagan. The senator said he would no longer support military aid to El Salvador unless the President certified that negotiations toward a political settlement were under way. Some observers took the Durenberger outburst to be a sign that sentiment in the Congress in favor of a negotiated settlement has increased significantly. Until recently, Senator Durenberger had supported the administration's policy toward El Salvador, including its requests for military aid.
A congressional staff specialist who is deeply involved in the current debate summed up the situation in this way: If Reagan tries to get the aid for El Salvador in the form of a supplemental appropriation from the Congress, he may well get the money, but not on the emergency basis that he favors. And if the President does get the money, he will have to pay a price in the form of political capital expended as well as in the form of conditions which demand an ever-increasing standard of performance from the Salvadorean government.
''What it boils down to is that there is not a majority in favor of terminating aid to El Salvador, but there is also not a majority which is enthusiastic about the policy,'' said the staff aide. ''There is a majority somewhere in the middle.''