WHILE ATTENTION focused on North Korea this week ahead of Friday morning’s missile launch, hundreds of Americans, Koreans, Japanese and others gathered in Washington to examine a different aspect of life in that communist nation: its “hidden gulag.”

That was the title of an unprecedented conference organized by the U.S. Committee for Human Rights in North Korea (HRNK) and the Jacob Blaustein Institute for the Advancement of Human Rights. The gulag is a network of labor camps that houses 150,000 to 200,000 prisoners. They are generally arrested for no crime, sent away with no trial, never again allowed to communicate with anyone outside the camps, fed on starvation rations and forced to work until they die. Other than from one camp, according to South Korean expert Yoon Yeo-sang, no one deported to North Korea’s gulag is ever released.

As noted by Blaine Harden, author of the recently published book “Escape from Camp 14,” the North Korean gulag has existed twice as long as did the Soviet network of labor camps created by Lenin and Stalin, and 12 times as long as Hitler’s concentration camps. Yet, for the most part, “Americans don’t know anything about these camps,” Mr. Harden said. “They don’t know they exist.”

This is not, the title of the conference notwithstanding, because the gulag is all that hidden, although North Korea’s regime continues to deny its existence. In fact, as David Hawk said, a great deal is known about the camps, both from the testimony of those who have escaped and from satellite imagery. Mr. Hawk has just published the second edition of his definitive survey, also called “The Hidden Gulag,” which draws on horrifying testimony from 60 former prisoners.

The reason for the ignorance is mostly political. The United States, with a goal of keeping the peace and depriving North Korea of nuclear weapons, has not made human rights a priority. In South Korea, the gulag has been a political football between left-wing politicians favoring warmer ties with the North and right-wing politicians pushing a harder line. China, North Korea’s neighbor to the north and west, abuses the human rights of its own population and does not believe any country’s freedom to abuse its population in the same way should be interfered with.

China, in fact, is complicit in North Korea’s abuses, since it sends many defectors who have made it across the Yalu River back into North Korea, where they face punishment or, if they are repeat escapees, execution. North Korean women who have become pregnant in China often are forced to abort their children. “In cases where the pregnancy is too advanced, guards beat the infants to death or bury them alive after they are born,” writes Roberta Cohen, the chair of HRNK.

Inevitably, there remains much that is unknown. It’s impossible to be confident of a population count for the gulag, Mr. Hawk said, because it’s not clear whether deaths are outpacing deportations.

Enough is known, however, for indifference to be inexcusable. As a first step, the United Nations could establish a commission of inquiry to investigate crimes against humanity taking place inside the prison camps. As Ms. Cohen said, “It is not just nuclear weapons that have to be dismantled but an entire system of political repression.”