We met over Memorial Day weekend on the terrace of the upscale Café Dupont on Dupont Circle in Washington, joined by his sister Hiwot, who runs a technology start-up in New York, and Iyassu, a 21-year-old former high-school track star who was starting work at a New York investment bank in the fall. Over white wine and chicken salad, the conversation touched on Lin-Manuel Miranda’s commencement address and Nega’s excitement over crossing paths, after the ceremony, with Donald Trump and Vice President Joe Biden. (Trump’s daughter and Biden’s granddaughter were members of Iyassu’s graduating class.) I asked Iyassu if he had reconciled himself to the idea of his father’s new life on the front lines, and he said that he had. “Ultimately he should continue to pursue what he believes in,” he told me. He expressed little interest, though, in visiting his father at his Eritrean rebel camp or delving deeper into the raison d’être of the Ginbot 7 movement. “I just got out of college — my life has its own direction,” he said. “I can’t take time off. ... I’m a little bit removed generationally as well.”

The elder Nega is part of a generation of Ethiopians who grew up amid violence and tumult. Over lunch, he recalled what it was like to be a high-school student when a Marxist junta, the Soviet-backed Derg, overthrew Emperor Haile Selassie and ushered in a brutal dictatorship. Nega had grown up privileged, the son of a wealthy entrepreneur, and he watched as his father’s vast commercial corn and soybean farms were seized and security forces began arresting, imprisoning and executing thousands of dissidents, including many students. He and his two older sisters joined a resistance movement called the Ethiopian People’s Revolutionary Party (E.P.R.P.). They went underground, living in safe houses, eluding the police. His eldest sister was later captured and disappeared in the Derg’s prisons. His family searched for her everywhere.

“We had people coming to our house and telling my parents, ‘I saw her at this place.’ My mother used to go out all over looking for her,” Nega recalls. Her former cellmates later told him that she had died in prison, probably by committing suicide with a cyanide capsule that she wore around her neck. “It was common to have cyanide with you because if you were caught, you would be tortured and executed, and through torture you might be forced to betray people,” Nega said. As the crackdown in Addis intensified, the E.P.R.P. sent Nega north to Tigray province, the center of a growing guerrilla war against the Derg; there, he carried out attacks on government forces. In 1978 a power struggle erupted within the E.P.R.P. leadership, and Nega was thrown into prison. He was released one day before guards turned their guns on the remaining prisoners, killing 15. Nega escaped to Sudan, living as a refugee in Khartoum for nearly two years, then obtained political asylum in the United States in 1980.

He earned his bachelor’s degree from the State University of New York at New Paltz, where he also played on the soccer team. While studying for his doctorate at the New School for Social Research, he lived in Brooklyn and wrote his dissertation on the failures of Ethiopian agriculture under the Communist regime. Meanwhile, Ethiopia was sliding deeper into calamity. When the guerrilla movements increased their attacks in Tigray in the mid-1980s, the Derg dictator, Mengistu Haile Mariam, blocked food supplies to the region, creating a devastating famine in which one million people died. Photographs of starving children, disseminated by the news media, catalyzed an international relief effort, Live Aid, and inspired the pop hit “We Are the World,” making Ethiopia a worldwide synonym for hunger. The famine had wound down, and the rebel war was escalating, when Bucknell hired Nega as an assistant professor in 1990. “He never trumpeted his background, the fact that he had been a guerrilla fighter,” says Dean Baker, a former Bucknell colleague who now heads the Center for Economic and Policy Research in Washington.

In 1991, after a decade’s struggle, three rebel groups — the Tigrayan People’s Liberation Front, the Oromo Liberation Front and the Eritrean People’s Liberation Front — defeated the Derg and marched into Addis Ababa. The new government, led by the Tigrayan rebel leader Meles Zenawi, set about rebuilding the war-shattered nation. Nega finally had reason for optimism. He knew Meles well — the prime minister had been in the same university class as his dead sister — and after the Tigrayans consolidated power, Nega obtained a leave of absence from Bucknell and flew with his wife and two sons, both toddlers, back to Addis, determined to help rebuild the country. Nega believed that Meles “had good intentions,” he told me.

But Nega’s enthusiasm for the new government wore off quickly. At Addis Ababa University, where he taught part-time (he had also taken over several of his father’s businesses), administrators cracked down on dissent, banning the student government and the school newspaper. When Nega encouraged his students to press for academic freedoms, police assaulted them and other demonstrators; later, as unrest spread through the city, they shot 41 people dead. Nega spent a month in jail for abetting the protests. “At night I was hearing prisoners being tortured, beaten,” he says.