Washington — In the midst of a new debate here over Central America, critics and defenders of Reagan administration policy alike agree on at least one matter: Hostility among nations in the region is growing, thus increasing the chances of a wider war.
The critics claim that the administration has contributed to this ''polarization'' by funding the so-called secret war conducted against Nicaragua's Sandinista-led regime. Administration officials respond that the Sandinistas themselves are responsible for provoking the hostility of their neighbors and increasing the risks of widening the war.
Administration officials also argue that pressure from the US-supported opponents of the Sandinistas has caused the Sandinistas to consider moves aimed at securing peace in the region.
This argument over a polarization of forces is one of the issues at the heart of the current debate in the United States Congress over American funding for rebel forces in Nicaragua. The House of Representatives prepared Thursday to vote on such aid, with House Democratic Party leaders predicting that the House would once again vote to cut off the aid. At the end of July, the House voted 228 to 195 to end further aid to the rebel forces.
As House debate began on Thursday, Intelligence Committee chairman Edward P. Boland, a Democrat from Massachusetts, said that with rebel attacks on oil depots and on the Managua airport, the conflict inside Nicaragua had intensified since the vote in July.
One of the administration's problems is that the rationale for the secret aid to the rebels has shifted along with the intensification of the conflict. Administration officials at first claimed that the aid was designed to build a program to interdict the flow of weapons from Nicaragua to El Salvador. When it became apparent that the rebels did not have this in mind, some administration officials argued that the aim was to put pressure on the Sandinistas. Among rebel leaders themselves, some said the aim was the overthrow of the Sandinista regime. But administration officials continued to insist that this was not their aim.
Requesting anonymity, one administration official said earlier this week that parallel to the debate in the Congress, there is a debate within the administration itself as to how far the US ought to go in putting pressure on the Sandinistas. William J. Casey, director of the Central Intelligence Agency, was reported to favor ever-increasing pressure, apparently in the hope that the Sandinista regime could be overthrown. But the administration official insisted that this was not the policy the administration had adopted.
Meanwhile, the Kissinger Commission on Central America was reported to have returned from its trip to the region struck by the degree of polarization that has taken place. In meetings with the commission, leaders in both Honduras and Costa Rica were said to have advocated tough action toward Nicaragua.
''Costa Rica, Honduras, El Salvador, and Guatemala are building toward a war with Nicaragua,'' an administration official said. ''But this is not our fault; . . . 99 percent of the reason for this polarization is Nicaraguan intransigence. The Nicaraguans started all this before we put any pressure on them.''
In a letter to House leaders delivered prior to Thursday's congressional debate, Secretary of State George P. Shultz argued that to cut off CIA support to the anti-Sandinista rebels would ''undermine the cause of peace and democracy'' and ''virtually destroy'' chances for a negotiated settlement in Central America.
But House Speaker Thomas P. O'Neill Jr. (D) of Massachusetts argued that Mr. Shultz was requesting support for a policy of arming rebels seeking the overthrow of a legitimate government.
If the House vote goes as expected - against covert aid - a long and difficult legislative process lies ahead. The Senate can be expected to vote next week in favor of the secret aid. Then a House-Senate conference committee would take up the matter. Finally, the Democrats, in an effort to block the aid, could still hold up the entire appropriation bill for all intelligence programs.
At his press conference on Wednesday, President Reagan defended such aid as legitimate:
''I do believe in the right of a country, when it believes that its interests are best served, to practice covert activity,'' said Reagan. But the President added that it would be impossible to let the American people know what was happening in Nicaragua ''without letting the wrong people know - those that are in opposition to what you're doing.''
The Sandinistas, however, claim to know fairly well what is going on. They charge that the administration has declared a war on Nicaragua that involves the United States ever more directly.
A source close to the Nicaraguan government said, meanwhile, that Nicaragua Foreign Minister Miguel D'Escoto Brockman was planning to present a new Nicaraguan peace plan Thursday to US Assistant Secretary of State Langhorne A. Motley. The source said the plan would be in the form of draft treaties and would cover in detail specific American concerns, including verification procedures to control the flow of arms and the withdrawal of foreign advisers from the region.