CALABAZO, Colombia — Several dozen Colombian paramilitary leaders were extradited to the United States in 2008, as the US war on drugs took precedence over the South American country’s own efforts to hold them to account. And leaving the country has turned out to be a benefit for them.

The extradited prisoners have received comparatively lenient treatment, despite being major drug traffickers who were also found responsible for massacres, forced disappearances, and the displacement of entire villages, an investigation by The New York Times found.

Once the paramilitaries have completed their US prison terms, they will have served on average seven and a half years. The leaders extradited en masse will have served an average of 10 years, at most, for drug conspiracies that involved tons of cocaine.

By comparison, federal inmates convicted of crack cocaine trafficking — mostly street-level dealers who sold less than an ounce — serve on average just over 12 years in prison.

Julio Henríquez Santamaría was leading a community meeting in the sylvan hamlet of Calabazo, Colombia, when he was abducted by paramilitary thugs, thrown into the back of a Toyota pickup and disappeared forever on Feb. 4, 2001.

Henríquez had been organizing farmers to substitute legal crops like cacao for coca, which the current Colombian government, on the verge of ending a civil war fueled by the narcotics trade, is promoting as an antidrug strategy.

But Hernán Giraldo Serna, or his men, didn’t like it, or Henríquez.

From his early days as a small-time marijuana farmer, Giraldo had grown into El Patrón, a narcotics kingpin and paramilitary commander whose antiinsurgent mission had devolved into a murderous criminal enterprise controlling much of Colombia’s mountain-draped northern coast.

Henríquez was hardly his only victim. But he became the emblematic one.

Henríquez had a family tenacious enough to pursue Giraldo even after he, along with 13 other paramilitary leaders, was whisked out of Colombia and into the United States on May 13, 2008, to face drug charges.

The extradition stunned Colombia, where the men stood accused of atrocities in a transitional justice process that was abruptly interrupted. In the whoosh of a jet, and at the behest of the Colombian president, Álvaro Uribe, Colombia’s efforts to confront crimes against humanity that had scarred a generation were dealt a major setback.

Victims’ advocates howled that it was like exporting “14 Pinochets.’’ But Henríquez’s family quietly vowed to hold at least one of them accountable.

“We hope that the effort we have made over all these years means that things won’t end with impunity,’’ said his daughter Bela Henríquez Chacín, 32, who was 16 when her father was murdered and hopes to speak at Giraldo’s sentencing in Washington next month.

The Henríquezes will be the first foreign victims ever given a voice in an international drug smuggling case in the United States, experts believe. Whether this recognition is more than symbolic remains to be seen.

For some of the extradited prisoners, there is a special dividend at the end of their incarceration: a green card. Though wanted by the Colombian authorities, two have won permission to stay in the United States, and their families have joined them. Three more are seeking the same haven, and others are likely to follow suit.

“In the days of Pablo Escobar, they used to say they preferred a tomb in Colombia to a prison in the United States,’’ said Alirio Uribe Muñoz, a member of the Colombian Congress. “But maybe now extradition is a good deal.’’

For 52 years, with abundant US support, the Colombian government has been locked in a ferocious armed conflict with leftist insurgents.

Though it initially empowered paramilitary forces as military proxies, the government withdrew official sanction decades later, long after landowners and cartels had co-opted them.

Before their demobilization in the mid-2000s, the militiamen came to rival the guerrillas as drug traffickers and outdo them as human rights abusers.

Now, eight years after the paramilitaries were extradited, Colombia has reached a peace deal with their mortal enemies, the Revolutionary Armed Forces of Colombia, also called the FARC.

Facing an Oct. 2 vote on the accord, the country is in the midst of a polarizing debate about crime and punishment for the FARC, informed by what went wrong during the paramilitary peace process. Nobody is advocating that justice be abdicated to the United States this time.