The Sandinista leadership has become increasingly disillusioned with appeals to liberal U.S. politicians and public opinion as a way to ward off hostility from the Reagan administration and prevent further U.S. funding for rebel guerrillas.

"There comes a time when you just have to stick to your positions," said an official in President Daniel Ortega's government.

The declining interest in currying favor in Washington marks a significant, if perhaps temporary, shift from previous Sandinista policy. Since the 1979 revolution, Nicaraguan officials had put heavy emphasis on promises of political pluralism and a mixed economy as a way to gain support among liberals in Congress and, more recently, to promote a halt to U.S. sponsorship of the anti-Sandinista rebels attacking from Honduras.

Diplomatic and Nicaraguan sources pinpointed as the major turning point a vote in Congress last July approving $27 million in nonlethal U.S. aid to the insurgents. This reversed a year-long refusal to permit official U.S. support for the rebels, often called contras from the Spanish word for counterrevolutionaries. In the eyes of some officials here, the vote also signaled a likelihood that Congress eventually would approve resumption of full military aid, as the Reagan administration now is seeking to do.

Ortega was overheard saying soon after the vote that the United States would continue hostility toward Sandinista rule in Nicaragua "even if we were little angels."

A trip to Moscow by Ortega right after an earlier vote against funds for the contras was cited by a number of congressmen as a reason for changing their minds on the $27 million. Ortega later explained the trip as a search for desperately needed oil deliveries. Nevertheless, it was interpreted by many in Washington as a political omen.

Diplomatic and Nicaraguan sources said Ortega and the eight other commanders in the ruling Sandinista Front's National Directorate appear to have concluded since then that U.S. support for the rebels is likely to continue at least through President Reagan's term no matter what they do. It is largely this conclusion, coupled with criticism from a number of former friends in Congress and elsewhere, that has diminished enthusiasm for the previous efforts to cultivate a better image in Washington, they added.

The most striking example of the new mood was a renewal and broadening last Oct. 15 of restrictions on civil liberties. The measures were announced dramatically as a new state of emergency, even though the Sandinista leadership had been quietly renewing similar restrictions every six months since March 1982. Since the announcement, the government has toughened censorship, closed the Roman Catholic Church radio and briefly detained for interrogation a number of political opponents, labor union leaders and Catholic and Protestant religious activists.

Commander Bayardo Arce a member of the National Directorate, told foreign reporters soon after the new measures were announced that their negative impact abroad was less important than "building the revolution" in Nicaragua.

In a similar vein, Ortega has warned indirectly that Nicaragua might supply Salvadoran guerrilla forces with portable ground-to-air missiles in retaliation for their use by the U.S.-backed Nicaraguan rebels to shoot down a Sandinista helicopter. Sandinista leaders previously had gone to great lengths to avoid allusions to their support for the Salvadoran guerrilla movement, which is one of the main Reagan administration arguments for supporting the Nicaraguan insurgents.

At Ortega's side as he made the oblique warning was Julio Lopez, head of foreign relations for the Sandinista National Liberation Front. The usual Sandinista practice has been to associate foreign policy with Foreign Minister Miguel D'Escoto, keeping Lopez out of the spotlight despite his considerable influence in delicate facets of Sandinista foreign policy such as relations with the Salvadoran rebels.

Despite the shift in emphasis, Sandinista leaders appeared particularly upset at charges of "religious persecution" made in New York last month by Cardinal Miguel Obando y Bravo. The prelate has become the most forceful opponent to Sandinista rule, largely protected by his status as Nicaragua's leading churchman, but had not previously used such strong language in public.

Sandinista officials accused the cardinal of seeking to lay groundwork for a favorable vote in Congress on the administration's request for resumed military aid for the rebels, expected to be made formally at the end of this month.

In what appears to be an attempt to impugn the church hierarchy, the government-controlled press has begun running articles on the Knights of Malta and Opus Dei with suggestions that the Roman Catholic lay organizations are part of a right-wing network linked to the Vatican and backing Obando y Bravo's resistance. A recent article in the Sandinista Front's official newspaper, Barricada, headlined a story on Opus Dei: "Another Mafia."

A companion progovernment newspaper, Nuevo Diario, has serialized the book "In the Name of God," which alleges that Pope John Paul I was assassinated.