Future peace talks between Nicaragua's leftist government and its Contra rebels are likely to have a political hue the Sandinistas never wanted. The government appeared to open the door to political discussions with its armed opponents by belatedly agreeing in principle last week to a proposal by the mediator of the negotiations, Cardinal Miguel Obando y Bravo, head of the Roman Catholic Church in Nicaragua. That proposal called on the Contras to accept a cease-fire in exchange for four major concessions by the Sandinista government. The concessions were something the Contras had been seeking, and they were quick to accept the cardinal's plan. The government was called upon to grant unrestricted freedom of the press and a total, unconditional amnesty for political prisoners, renew a dialogue with its internal opposition and review its universal military conscription law. Whether it was a tactical error or a considered response, the Sandinistas delayed in taking a position that President Daniel Ortega has long and strenuously opposed. On innumerable occasions in the past, he has said he would never discuss political matters with the Contras. ``We don't want to create the impression that we don't want a cease-fire and are being intransigent,'' said Paul Reichler, a Washington, D.C., attorney who advises the Sandinistas. ``At all costs, we want the negotiations to go forward.'' Reichler's comments came in a chat with reporters Friday after Obando y Bravo abruptly suspended the latest round of peace talks a day before they were supposed to end and obliquely blamed the Sandinistas for the breakdown. Ortega said Saturday in Managua that the cardinal's proposal ``was not rejected'' by the Sandinistas and said his government ``is willing to continue the conversations.'' But a clarification was needed on the withdrawal of the Contras to enclaves during the truce, Ortega said at the close of a government meeting. He repeated that his government is willing to apply an amnesty once a cease-fire is in effect. Referring to the military draft, he said ``it is logical that with the end of the war the military service will not require the current volume (of soldiers).'' Ortega told the meeting on new economic measures aimed at fighting inflation that ``enemies of the revolution'' opposed the measures. He said the right, the extreme left and the opposition daily La Prensa should be careful not to stir up insurrection. The cardinal said after his return to Managua on Saturday that with the suspension of talks, ``We have given time for reflection since there is a lack of trust between the two sides.'' Appearances are of vital importance to both sides, with neither party wanting to be seen as the spoiler as long as there is any remaining chance the U.S. Congress might approve additional military aid for the Contras. In private talks with reporters, the Sandinistas made it clear that they were initially surprised by the cardinal's five-point proposal, then disappointed by his abrupt cancellation of the talks. Victor Hugo Tinoco, Nicaragua's deputy foreign minister, said Obando halted the negotiations Friday afternoon before he had a chance to deliver the government's formal, written response to the proposal the cardinal put forth Thursday. But Tinoco insisted that he had discussed the government's position at length with the cardinal Friday morning and had not been given any reason to believe that the cardinal was unwilling to continue the negotiations. The cardinal ``did not tell us he disagreed'' with the government's position, Reichler told reporters later. In its written response, the government declared its ``agreement in principle'' with the cardinal's proposal, but carefully conditioned its answers to his requests that it reconsider its mandatory draft law and grant an unconditional amnesty to the thousands of political prisoners in Nicaraguan jails. But before Nicaragua's formal response was delivered, Obando had canceled the talks, saying he was disappointed that both sides had not accepted his proposal, at least in principle. The remark was clearly aimed at the Sandinistas. But late or not, the government's response clearly put such political matters as press freedom and amnesty on the bargaining table for further talks and, given the opening, the Contras are likely to push for even greater concessions. The cardinal is expected to announce a time and place for a third round of face-to-face negotiations sometime this week. The first round of talks took place in San Jose, Costa Rica, in late January, only a week before the House rejected President Reagan's latest request for about $43 million in additional Contra aid. But the administration is considering a new bid for military aid for the rebels, and as long as that possibility exists, both sides will be playing their cards cautiously at the bargaining table.