The expanding civil war in Nicaragua has aroused intense passions throughout Latin American in much the same way that the Spanish Civil War polarized world opinion more than 40 years ago.

Last week, the Trotskyite Socialist Workers Party here in Colombia announced the formation of the Simon Bolivar Brigade, which has already sent its first volunteers to fight alongside the Nicaraguan rebels. In Chile, university students forbidden to protest their own military government have boycotted classes, risking expulsion, to show their opposition to the Nicaraguan government of President Anastasio Somoza.

"We are certain that this is a historic moment, like the revolution in Cuba, that signifies a total change," explained Socialist Workers Party official Luis Carlos Valencia, who is due to leave here shortly to join the Sandinista rebels in Nicaragua.

Gustavo Gonzalez Boano, a 21-year old poet and self-described revolutionary who signed up for the Bolivar Brigade, said he was joining the anti-Somoza fight because "the battle in Nicaragua is the battle of all Latin America. The cause in Nicaragua affects all of us. We must be a part of the cause if we are to live in dignity."

There is hardly a university in any major Latin America city that does not display slogans in support of the revolt being led by Sandinista guerrillas in Nicaragua. And there is hardly a nation on the continent where the question of breaking relations with the Somoza government has not sparked national debate.

Thus far, Mexico, Costa Rica, Panama and Ecuador have severed official ties with Nicaragua. Last weekend, the five Andean Pact countries - Peru, Ecuador, Colombia, Bolivia and Venezuela - declared the Sandinista guerrillas to be a regular army, not simply terrorists as Somoza has claimed, a step that could pave the way for direct support for the Sandinistas.

There has been no shortage of volunteers for the Bolivar Brigade here in Colombia. Most are men in their twenties, but there are also women and older people. The eventual size of the brigade, which will fight as a unit but be subject to the Sandinista chain of command, will be from 70 to 100, according to party leader Valencia.

Volunteers are asked to provide personal data about themselves, although they need not be memebers of the Socialist Workers Party.

"We aren't interested in tourist, adventurers or persons with criminal charges against them," Valencia said, "nor are we interested in spies or the police."

Pro-Somoza forces have also mobilized in several Latin nations, but none are known to have sent soldiers to help defend his government. Last April, the World Anti-Communist League met in Asuncion, Paraguay, and expressed its unflagging support for Somoza's battle against the leftist rebels.

By sending the Bolivar Brigade, Colombia's Socialist Workers Party hopes to influence the policies of the Sandinista movement. Valencia said he hopes the Brigade's presence will persuade Sandinista leaders not to accept any coalition with "bourgeois forces" if Somoza falls.

"Objectively, the fall of the Somoza dictatorship will be the fall of a dictatorship imposed by the Yankee imperialists." Valencia said.

"One of the most important aspects of the brigade is its anti-imperialist feeling, to demonstrate that this feeling is not just in Nicaragua but in all of Latin America."