MANAGUA, NICARAGUA, JULY 11 -- A year ago, on the eve of the Sandinista revolution's triumphant 10th anniversary, a former guerrilla commander and top government official mused on what she considered the remote possibility of the party's defeat in upcoming elections.

The Sandinistas would not accept defeat easily, she said. "Remember what happened the last time we were in opposition? A new government wouldn't last two weeks."

Now, four months after national elections turned the revolutionary party out of power, the Sandinistas have issued a violent reaffirmation of their determination not to be excluded from power -- despite February's popular mandate.

In a paralyzing general strike that exploded into the bloodiest political turmoil in Ma-nagua since the 1979 insurrection, the Sandinistas vowed they would take "not one step back" in defending the "conquests of the revolution."

By the time the anarchy on the streets was under control today, five people were dead and nearly 90 injured, including supporters of the 11-week-old government of President Violeta Chamorro, Sandinista stalwarts and two policemen. The violence ebbed after an emergency meeting Tuesday night in which both sides expressed a willingness to negotiate.

Sandinista labor unions have proclaimed they would fight to the last to protect workers and peasants -- a clear majority of whom voted for Chamorro -- from the new government's attempts to trim the public payroll, sell state-owned industries and return confiscated land to its original owners.

But the more fundamental struggle is about power. Facing a shifting political dynamic that threatened to leave them on the sidelines, the Sandinistas drew a line in the dirt.

Their message: Bargain with us -- or face the consequences. Having won international praise for relinquishing power peacefully in April, the Sandinistas are demanding what amounts to an absolute veto over major government policies.

The strategy was clearly forecast by Sandinista leader and former president Daniel Ortega, who told his supporters in a speech two days after his electoral defeat, "We're going to govern from below." And in recent days it has been reiterated by strike leader Lucio Jimenez, coordinator of the Sandinista-backed National Workers' Front, who said Tuesday that unless the government negotiates, "what could happen is something uncontrollable -- complete and total anarchy."

The strategy is rife with political risk for the Sandinistas. The party demonstrated in the elections that it represents a minority of Nicaraguans, and the inconveniences of the strike have probably cost it further support.

The workers' front today urged strikers "to create conditions favoring the start of talks, allowing circulation of people and transport." In turn, Chamorro agreed to talks once strikers vacated government offices.

The gunplay, street barricades, burning tires, molotov cocktails and tough talk have provided a vivid reminder of the tenacity of Nicaragua's deep social divisions. Embittered by more than a decade of civil war and insurrection, it is a society that will not be quickly healed by Chamorro's soothing words about national reconciliation and amnesty, nor by her success in disbanding the U.S.-backed contras in the first two months of her administration.

Despite her margin of victory, 55 to 41 percent, and personal popularity, the president cannot easily paper over the basic shift she is attempting to make -- from a centralized economy dominated by the public sector to a free-market system that favors private producers.

The political battle lines are not drawn simply between Sandinistas and anti-Sandinistas, but rather among a host of bickering factions on both sides. Sandinista leaders, perhaps seeking to distance themselves from the inconvenience and violence that gripped the capital, said during the strike that while the party supported the strikers, it did not exercise full control over the actions of hard-line labor leaders.

In the Chamorro administration, the new president and her tight circle of technocratic advisers for months have maintained a frosty distance from the National Opposition Union, the coalition of 14 political parties ranging from conservatives to Communists that ran with her in February.

Many of the more conservative politicians have grumbled that Chamorro's current troubles are rooted in her decision even before she took office to make key concessions to the Sandinistas, such as leaving them in substantial control of the army and the police.

At a news conference Tuesday, the National Opposition Union said it had formed a National Salvation Committee to deal with the national crisis. But hours later, Chamorro issued a statement appearing to rule out any meaningful role for "any extra-governmental body" in "functions that belong only to the constitutional government."

The ongoing split between Chamorro, who does not belong to any political party, and the coalition elected to govern with her illustrates the president's profound politicial isolation. She seems to lack the ability to mobilize her supporters, and even her government, in crises.

Non-Sandinista radio stations seem more loyal to the hard-line elements of her government, led by Vice President Virgilio Godoy, than to her. And at the height of the crisis on Monday night, Chamorro did not even have control of the television broadcast center, which had been abandoned by government officials and taken over by Sandinistas.