Former NBA star Dennis Rodman carved a niche for himself in the 1990s among aficionados of rebounding, hair dyes and bizarre but harmless public behavior. The fun turned rancid a couple of years ago, when the former player's attorneys explained to a court that he could not pay $800,000 in overdue child support because he was "broke" and "extremely sick" because of alcoholism.

Now Mr. Rodman is attempting to rehabilitate himself and his bank account by serving as a propagandist for one of the world's cruelest and most brutal dictators, Kim Jong Un of North Korea. On Wednesday, in a grotesque replay of Marilyn Monroe, he crooned "Happy Birthday to You" to the 31-year-old tyrant before playing an exhibition game in Pyongyang with other washed-up pro basketball players. This came after he proclaimed his "love" for his "friend" and responded to a question about an American held prisoner in a North Korean labor camp with a rant suggesting that he deserved to be there.

As the State Department and NBA hastened to make clear, Mr. Rodman is not engaged in a legitimate exercise of sports diplomacy — and his antics are anything but amusing. The ruler he is promoting is emerging as a reckless and brutal tyrant who just summarily executed his uncle — a man who apparently was attempting to foster greater openness in one of the world's most isolated countries. As escapee Shin Dong-hyuk pointed out in The Washington Post last month, Mr. Kim presides over a system of labor camps used "to punish, starve and work to death people who the regime decides are a threat."

One inmate of that gulag is Kenneth Bae, who was arrested more than a year ago while leading a business tour; he was sentenced in May to 15 years of hard labor. According to his family, Mr. Bae has lost more than 50 pounds and his health has rapidly deteriorated. Yet the Kim regime has ignored appeals for his release on humanitarian grounds.

Mr. Rodman happens to be the only American, and one of the few foreigners, with access to the young leader. Mr. Kim has partied repeatedly with the former Chicago Bull, but he has yet to meet a foreign head of state. Yet when Mr. Rodman was asked after a previous visit about whether he had raised Mr. Bae's case with Mr. Kim, he said, "That's not my job." That was before his obscene rant about Mr. Bae on CNN Tuesday, which caused at least one of his fellow basketball mercenaries to express remorse for joining the tour.

It wouldn't be surprising if the callow Mr. Kim were to conclude that, thanks to Mr. Rodman, he doesn't need to free Mr. Bae in order to win good will in the United States. As the prisoner's sister puts it, that is "no diplomacy"; it is "playing games with my brother's life."