With his major speech on Central America, President Reagan appears to have changed few minds in the United States Congress. But the President seems to have succeeded in leaping over the Congress and going directly to the people. If telephone calls to the White House are any indication, Reagan has added at least slightly to support for his stated aim of halting communism in Central America.
In the Congress itself, there was considerable criticism of the speech, mostly along partisan lines. Many Democrats found that President Reagan, in his major address on Wednesday night, dwelled too heavily on the need to confront the Soviets, Cubans, and Nicaraguans, and not enough on the need for reform, economic development, and negotiation in the region.
Most regrettable, as far as some members of Congress were concerned, was the relatively short amount of time Reagan devoted to US efforts to achieve peace in the region. The President said that the US ''fully supports'' the objectives of the so-called Contadora group of nations. But there is considerable doubt both here and in the region itself that this is indeed so.
The World Court decision Thursday to order the United States immediately to stop mining Nicaraguan ports and to end all military operations against leftist-led Nicaragua seemed merely to reinforce the view of some congressional critics that the US was wrong in its approach to the region. The verdict delivered by court Judge Taslin Olawale Elias of Nigeria followed the first suit to be filed against Washington by a third-world nation.
''The verdict does solidify the view up here that the US should not be engaged in this sort of covert activity,'' said Rep. Michael D. Barnes, the Maryland Democrat who heads the House subcommittee on Western Hemisphere Affairs.
Barnes said in a telephone interview that he was among those who did not think that President Reagan's major speech changed any minds on Capitol Hill.
But regardless of the doubts and criticisms, President Reagan's aid proposals for Central America appeared, at this writing early Thursday, to be moving forward in the Congress in at least one form or another. The reasons seemed to be several. Perhaps most important was the apparent election victory in El Salvador of presidential candidate Jose Napoleon Duarte, a Christian Democrat regarded as a moderate battling extremes who is genuinely popular among many senators and congressmen.
But there was also the ''fear factor.''
As House Speaker Thomas P. O'Neill Jr., a Massachusetts Democrat, explained it to reporters Thursday in answer to questions about the Reagan speech, ''The President was very effective, mostly because (he made members of Congress think): 'What kind of a mess would I be in in my district if El Salvador fell to the Communists?' ''
''Every other year, there's a timidness on both sides,'' said Mr. O'Neill, referring to election-year votes.
O'Neill, who opposes El Salvador military aid, predicted that the President's proposals for such aid will prevail.
Nearly everyone interviewed, however, including O'Neill, agreed that the House-Senate conference set for next week was unlikely to provide more support for the CIA-supported ''contra'' rebels fighting in Nicaragua. One exception was Republican Sen. David Durenberger of Minnesota, a member of the Senate Select Committee on Intelligence, who said he thought some form of support for the contras might go forward in the context of tight restrictions and an end to the mining of ports.
President Reagan placed little emphasis on the contras in his speech, apparently not wanting to revive any of the controversy over the mining issue.
According to Senator Durenberger, members of Congress who returned to their districts and states recently found that the mining was an issue in some places but a mere ''ho-hum'' subject in others.
Asked, meanwhile, why President Reagan in his speech seemed to avoid the issue of the four Contadora nations' peace efforts, Speaker O'Neill said, ''I don't understand it, since those nations understand the culture . . . I'm greatly disturbed by what I see. The President is Americanizing the war.''
The foreign ministers of the four Contadora nations - Colombia, Mexico, Panama, and Venezuela - met in Panama City last month with Central American counterparts. But despite a moderately positive-sounding bulletin issued on May 1, State Department officials described the meeting was inconclusive.
The Contadora nations appear to be divided among themselves. Some US officials, while formally supporting the Contadora process, have doubts about it , particularly when it comes to the views held by Mexico.Nicaraguan positions on some issues, including the issue of monitoring the flow of arms into Central American nations and across borders, have hardened, officials say.
In a confidential cable, dated April 30 and first reported by the Hearst newspapers, the US ambassador to Nicaragua described a situation in which the pressure being exerted on Nicaragua, far from achieving its stated goal of moderating Sandinista behavior, had hardened that behavior. As Ambassador Anthony Quainton described it in his report to the State Department, the ruling Sandinista National Liberation Front (FSLN) adopted a softer policy last November following the Grenada invasion but was convinced by the increased contra activity and the mining that the Reagan administration sought the regime's destruction.
In a letter to senators, President Reagan has explicitly denied that this is the administration's aim. But Mr. Quainton's cable, obtained by this newspaper, puts it this way: ''For its part, the FSLN has abandoned the conciliatory policy it adopted last November in the wake of the Grenada operation. . . . The mining of the ports and the escalation in contra activities has convinced FSLN leaders that a soft-line policy is hopeless, as the USG (US government) is determined to destroy the revolution.''