When Carmen Mejia set out the other afternoon, she thought it was just another Sandinista Youth mission to stir support for the revolution among her fellow university students.

By the time 90 minutes had gone by in the classroom, however, Mejia had been made painfully aware that many students at the University of Central America here deeply resent the obligation to interrupt their studies to serve in Sandinista coffee-picking brigades.

"We want to know what your problems are," Mejia began, campus-styled in a boyish haircut and a sweatshirt imprinted with a Snoopy picture.

She went on to organize a reading of a tract outlining how the Sandinista revolution overthrew the Somoza dictatorship and ended repression of students, but now was facing aggression from the "will of imperialism" in the United States.

Students, invited to comment, at first were hesitant. Then it began.

"What would you call it when they refuse to give you your enrollment for next year if you do not pick coffee?" asked a girl in the front row with a pink ribbon tying her hair in a ponytail. "What would you call that if it's not repression?"

Mejia, 21, attempted to answer: "We are the rear lines. Nobody said that because we are sitting here in this classroom that we have peace."

She said she could "clarify," explaining that because so many peasants are in the Army, forced to expand by U.S.-supported insurgency, students have a duty to pick coffee in their place.

"I don't need clarification," responded another student, a tall girl in rust-colored slacks. "I have listened to what you said. And I agree with most of it. But the final word will be ours. We will see what happens to the students who refuse to go pick coffee."

Mauricio Blanco, 27, assistant dean of administrative sciences, stepped in to assure the students that given Nicaragua's situation no student could interpret participating in Student Production Battalions as an undue requirement. It is not an obligation, he added, and the students smiled.

Under persistent questioning, Blanco later acknowledged that students who fail to report for coffee-picking duty without a valid excuse will not be promoted.

Listening through the open window, other students gathered on the pathway outside. As the conversation heated up inside, it moved outside as well.

"Because we don't want to go, they won't promote us to the next year, and then they say this is not repression," said an interested bystander.

"Okay, so it's repression," another responded. "If you don't like it, go off to Miami. There's no repression there."

The first bystander shot back: "No, I'm not going to Miami. I don't want to. I am Nicaraguan. This is my country."