When President Jimmy Carter commuted the prison sentences of the four living Puerto Rican nationalists who launched attacks against members of Congress and President Harry S. Truman in the 1950s, he cited “humane considerations.”

Critics wondered whether there were other motivations.

In 1979, Carter freed three Puerto Ricans who had shot and wounded five members of Congress, and an attacker who had attempted to kill Truman.

“I freed them because I thought 25 years was enough,” Carter said at the Congressional Hispanic Caucus dinner, to a mix of catcalls and cheers.

Carter’s secretary of state, Cyrus R. Vance, concluded that their release “would be a significant humanitarian gesture and would be viewed as such by much of the international community” - a statement that was in sync with a president who made human rights a priority.

But foreign and domestic political factors were at play, as well. Cuban President Fidel Castro, who backed Puerto Rican independence, had offered to free four Americans jailed in Cuba for political crimes if the United States released the Puerto Rican nationalists; soon after Carter freed the four Puerto Ricans, Castro made good on his offer.

The Puerto Ricans’ release also took place on the eve of an election year, when Carter was facing a tough Democratic primary challenge from Sen. Ted Kennedy of Massachusetts. Although Puerto Rico didn’t, and still doesn’t, have a vote in presidential general elections, it was set to have its first presidential primary in 1980.

“With straight faces, White House aides deny any link between the release of the prisoners and the island’s 41 Democratic convention delegates,” Time magazine sneered at the time. (Carter wound up narrowly defeating Kennedy in the Puerto Rico primary.)

The attack on the Capitol had occurred March 1, 1954. Four members of the Puerto Rican Nationalist Party entered the spectators gallery with handguns, at a time when there was minimal security on Capitol Hill. Shouting “Viva Puerto Rico libre!” they unfurled a Puerto Rican flag and shot indiscriminately into the House chamber.

“Five Congressmen Wounded in House by Shots of 4 Puerto Rican Terrorists; Bentley Given ‘50-50’ Chance to Live,” ran a three-line headline across the top of the next day’s Washington Post. Alvin M. Bentley (R-Mich.), who had been shot in the chest, was the most seriously wounded congressman. But he and the other four members who were struck that afternoon all recovered.

The attackers were Lolita Lebrón, Andres Figueroa Cordero, Rafael Cancel Miranda and Irvin Flores Rodríguez. Cordero was freed two years before the others, when Carter in 1977 commuted his sentence on “humanitarian grounds” because he was terminally ill with cancer. Cordero expressed no remorse for the attack, saying in an interview a year after his release that he did it to draw attention to the fight for Puerto Rican independence and “the colonial situation of our people.”

“I would do it half a million times if I had to. To save your country, there is no other recourse than to give your life,” said Cordero, who died in March 1979 in Puerto Rico, which was a Spanish colony for four centuries before Spain transferred the island to the United States in 1898 after the Spanish-American War.

The attack on Truman took place in 1950, when Puerto Rican nationalists Oscar Collazo and Griselio Torresola tried to shoot their way into Blair House, where Truman was living temporarily during renovations to the White House across the street. A White House guard was killed, along with Torresola. After Collazo’s conviction on four counts, including premeditated murder of the White House guard, he struck a defiant tone at his 1951 sentencing hearing.

Addressing federal Judge Alan T. Goldsborough, Collazo said: “I’m not pleading for my life. I’m pleading for my cause. Anything I may have done I did for the cause of my country. I use this last plea for the right of my country to be free. Even if I die today, and I realize the Americans have the right to kill me, they will never be able to kill the ideals I stand for.”

Goldsborough lectured Collazo on how Puerto Rico was much better off as part of the United States than under Spanish rule and said he felt sorry for the defendant. Then he sentenced Collazo to death.

But in 1952, Truman commuted Collazo’s sentence to life in prison about a week before he was to be executed by electric chair. That year, Puerto Rico became a U.S. commonwealth, allowing it to draft its own constitution with a measure of self-rule.

“The president prides himself as one who has done more for Puerto Rico than any other president,” the New York Times wrote at the time. Truman had appointed the first native Puerto Rican as governor in 1946 and visited Puerto Rico in 1948.

In a historical twist, Robert Garcia, who as a teenager lived next door to Collazo in the South Bronx at the time of the 1950 attack, led the effort to free him and the surviving Capitol Hill attackers as a Democratic congressman in the late 1970s.

“I’m not a nationalist, I’m not an independista,” Garcia said in a March 1979 interview. “I just want to do what I think is right. These people have served longer than anybody who has ever been convicted of crimes like theirs. They’ve served plenty of time, and enough is enough.”

Garcia, who was the only voting member of Congress of Puerto Rican descent, put together a coalition of lawmakers to rally for the cause. Some of the island’s politicians and religious leaders supported the effort. But Puerto Rico Gov. Carlos Romero Barceló urged Carter not to release the nationalists unless they showed remorse and vowed to eschew violence. Without those concessions, he warned, a release “would constitute a menace to public safety.”

The jailed Puerto Ricans had refused to seek clemency, claiming they were political prisoners. And after Carter released them, they pointedly refused to rule out violence. Before returning to Puerto Rico, they appeared at receptions in Chicago and New York, demanding Puerto Rican independence. They expressed no gratitude toward Carter. Their release, insisted Lebrón, the ringleader of the Capitol attack, “was done for political expediency and not because of a concern for human rights.”

“I am a revolutionary and a member of the atomic age. ... I hate bombs, but we might have to use them,” she said at a United Nations news conference, while Collazo insisted, “I decide whether terrorism is necessary after I return to Puerto Rico.”

They received a hero’s welcome upon landing at the San Juan airport, where 6,000 Puerto Ricans surged against police lines and tore down fences, chanting “Lolita! Lolita!,” “Viva Puerto Rico libre!” and “Jíbaros si, Yanquis no” (“Puerto Rican farmers yes, Yankees no”). Collazo’s 45-year-old niece rushed to hug him, then suffered a fatal heart attack.

“We have done nothing to cause us to repent,” Lebrón told the crowd. “Everyone has the right to defend his God-given right to liberty.”

Frederic J. Frommer, a writer and sports historian, is the author of several books, including “You Gotta Have Heart: Washington Baseball from Walter Johnson to the 2019 World Series Champion Nationals.”