The resignation last week of the two moderate members of Nicaragua's revolutionary junta has dropped the struggling government into its deepest political crisis since the end of the civil war last July and sent Sandinista leaders scrambling to repair bridges to the country's business community.

Events following the resignation last Tuesday of businessman and centrist politician Alfonso Robelo showed the difficulty of government efforts to balance the demands of radicals for socialist measures against the government's professed commitment to democracy and political pluralism.

Tens of thousands of Nicaraguans waving Sandinista flags and upraised fists gathered beneath the blistering sun Saturday to denounce Robelo as everything from a coward and opportunist to a "bourgeois traitor."

The quieter side of the reaction, however, suggests that Nicaragua's Sandinista leaders may be willing to make considerable compromises to keep the good will of the business interests Robelo was usually seen as representing while a member of the five-member junta.

Ranking Sandinistas announced their desire to restore business representation to the junta and have been in a most constant contact with leaders of the principal business organizations in the country in a series of formal and informal meetings held last week. According to one informed observer, "A climate of good will has been shown by both sides."

Robelo's resignation, which had been rumored since he turned his National Democratic Movement into a de facto opposition party last month, finally came at a particularly difficult time for the nine-month-old revolutionary government.

Violeta Chamorro also a non-Sandinista, resigned from the junta, citing health and family reasons, on April 19. The next day, her family newspaper, La Prensa, the only independent newspaper in the country, was shut down by a strike.

On April 21, the government announced a fundamental change in the proposed council of state, expanding Sandinista representation from the one-third agreed to in the original government plan to a clear majority. Robello, who had opposed this move vehemently, resigned the next day.

Fears that the Sandinistas were moving to crush political and press freedom further jeopardized the uncertain future of a $75 million aid package, now stalled in Congress, which is desperately needed both for economic reasons and to give a psychological boost to the business community.

Robelo has joined Sandinista leaders in making repeated calls to Nicaragua's congressional supporters to persuade them that the aid package should go through regardless of the political infighting here.

Businessmen, diplomats and Robelo's people suggests, moreover, that far from being the end of democracy in Nicaragua, the current crisis is the real beginning.

One influential Latin American diplomat said he believed that, despite Sandinista denunciations, the establishment of a full-fledged opposition party will be a stabilizing influence by providing peaceful, challenging dissent.

Nevertheless, serious problems remain. Sandinista junta member Sergio Ramirez said at a press confernce Friday that Robelo cannot return to Nicaragua's business sector.

Other well-informed sources believe that the vacancies will be filled by a representative of the Private Enterprise Council and a respected non-Sandinista member of the government.

In the meantime, however, the council is making fundamental demands as prerequisites for cooperation.

The demands are said to include an end to confiscations of land and other private holdings, a set deadline for municipal elections, guarantees of press freedom and a low permitting private citizens to appeal government actions in court. The junta announced today that the appeal law would be made public within a few days.

The most fundamental problem, according to businessmen, is a lack of credibility on the part of the Sandinistas, who are under pressure from their own mass organizations and leftwing extremists to take more radical socialist measures.

The Sandinistas' pragmatic revolutionary leadership, realizing the threat to their already war-ravaged economy that massive expropriations would cause, generally have sidestepped the radical demands. But some nominally illegal land seizures by peasant groups have been accepted by the government after the fact, greatly angering the private sector.

There is also the basic fear, as Robelo put it, that "the Sandinistas now think they own the revolution."

Rebelo points out that the over throw of the dictatorship of Anastasio Somoza depended on a broad-based alliance in which the support of the private sector and other parties played a crucial role.

Nevertheless, many Nicaraguans identify the success of the fight against Somoza exclusively with the Sandinista guerrillas, and the Sandinistas do everything in their power to encourage his viewpoint.