MANAGUA, Nicaragua — In an unexpected challenge, 14 parties spanning the political spectrum have united behind demands that would bar President Daniel Ortega from reelection and weaken the ruling Sandinista Front's control over the army headed by his brother.
The Ortegas have responded by warning, with some of their most belligerent rhetoric in months, that the opposition is treading dangerously close to the limits of acceptable dissent.
Faced by a coalition ranging from Communists to conservatives, a Sandinista representative refused this week to negotiate most of its 17 demands, prompting the opposition bloc to walk out of a "national dialogue."
The dialogue, which began in October, is mandated by the Central American peace accord as a forum to negotiate democratic reforms. In parallel cease-fire talks with U.S.-backed rebels, the Sandinistas have refused to discuss political issues underlying the guerrilla war. Instead, they insist that exiled rebel leaders first renounce armed opposition, then come home to press their demands through the dialogue.
But opposition leaders said in interviews Friday that the dialogue had broken down. Some said it has been undermined in part by a high-level Sandinista defector's disclosure in Washington of secret plans to double the size of the Nicaraguan armed forces with assistance from the Soviet Union.
This disclosure, by former Maj. Roger Miranda Bengoechea, has shaken Managua's confidence that the U.S. Congress will stop aiding the Contras with funds and has hardened its resistance to a democratic opening, opposition leaders said.
"The peace agreement and the dialogue are just a game for the Sandinistas," declared Enrique Alvarez Montalvan, a Conservative Party leader. "As long as they can use the game to stop aid to the Contras, they will play. But if what Miranda said has a decisive impact on Congress, then the game is over."
On Thursday, activists of the 14 parties marched to the office of Cardinal Miguel Obando y Bravo, the Roman Catholic primate. They handed him a letter saying that the Sandinistas had refused to consider "reforms necessary for the democratization of Nicaragua" and launched "a campaign of threats against the opposition."
Overcoming a history of intense squabbling, opposition parties inside and outside the National Assembly negotiated their demands among themselves over a period of several weeks.
They call for ending Sandinista party control over the armed forces, the electoral process and the judiciary. They would limit presidential power, allow conscientious objection to military service and prohibit members of the armed forces from voting. Private property guarantees would be strengthened.
Carlos Nunez Tellez, the Sandinista representative in the dialogue, said the government "respects but does not share" these proposals. He said he would submit them to the assembly, over which he presides, without the government backing needed to approve them as constitutional amendments.
He agreed to consider other plans, including more autonomy for town governments and the appointment of an independent prosecutor for human rights abuses.
But he rejected the two most important opposition demands, which would bar any president from succeeding himself or being succeeded by a blood relative or an in-law.
Opposition leaders said they want to prevent another family dynasty like that of the late Anastasio Somoza Garcia and his two sons, who ruled Nicaragua for 43 years.
The Ortegas have emerged as the most prominent of the nine Sandinista comandantes who came to power as equals in an insurrection that toppled President Anastasio Somoza Debayle in 1979. Daniel Ortega, now 41, was elected president in 1984 for a six-year term. His 39-year-old brother is minister of defense.
President Ortega has assumed direct responsibility for assuring that Nicaragua lives up to its obligations under the Aug. 7 peace accord.
But in a speech last Sunday, he warned opposition leaders that they could lose their political rights if they lend themselves to plotting by the Reagan Administration to create internal divisions that could lead to an American invasion.
"We cannot permit a so-called civic opposition to turn into a representative of the Contras inside our country, because that would provoke the workers and peasants," he said. "The government could be a little more patient, but the people can lose patience very quickly."
Speaking a day earlier, Humberto Ortega said opposition leaders risked reprisals for what he called "seditious, subversive attitudes."
"The (political) right should not think that the workers will not force them to pay historically, and even more if there is more war," he said. "Let the right tremble before the justice dealt by our people."
Neither brother mentioned the opposition demands. But diplomats said that the Sandinista Front is racked by insecurity over Nicaragua's economic collapse and a fear that concessions under the peace accord have strengthened their foes without stopping the war.
"The Sandinistas thought that the opposition would always be divided," a Latin American diplomat said. "But what happened is that they created a real political space. It isn't very big, but it is real, and now they are threatening to close it."
The opposition newspaper La Prensa, which helped shape and publicize the 14 parties' demands, said in an editorial that the Ortegas should fear a stepped-up war "only if they are not thinking of complying (with the peace accord) and insist on militarizing the country."
Times staff writer Marjorie Miller contributed to this story.