Treasury Secretary Steven Mnuchin has said he is considering lifting the sanctions altogether because they are punishing the “hardworking people of Rusal.” But Mr. Mnuchin has it backward. If he was truly concerned about Rusal’s 61,000 employees, he would not relent until the company fully washed its hands of Mr. Deripaska and the corrupt regime the aluminum giant serves.

Behind Mr. Deripaska’s estimated fortune of as much as $5.3 billion, there stands a great crime. During the “aluminum wars” of the 1990s, when that economic sector was consolidating in the chaotic privatization that followed the collapse of the Soviet Union, the young metals trader was suspected of ties to gangsters as he seized control of huge Siberian smelters. According to testimony by a gang member in Stuttgart, Germany, part of Mr. Deripaska’s value to the group were his links to Russia’s security services. While his rivals were killed off or fled Russia, Mr. Deripaska somehow emerged as the director general of Rusal, a company that reported revenues last year of nearly $10 billion. But suspicions that the oligarch has had links to organized crime have denied him a visa to enter the United States.

Mr. Deripaska is little more than a trustee for his aluminum concern. In Russia, oligarchs like him owe their wealth and status to the Kremlin. In return, they must do its bidding, which in Mr. Deripaska’s case meant spending more than $1 billion, through his holding company, on new infrastructure for the 2014 Winter Olympics in Sochi, Russia. Mr. Deripaska has embraced his role, stating that he does not separate himself from the Russian state. In line with that conceit, a memo obtained by The Associated Press showed that Mr. Manafort tried to pitch him a plan for an influence campaign to “greatly benefit the Putin government.”

Mr. Deripaska was sanctioned on April 6 by the Treasury Department’s Office of Foreign Assets Control for “having acted or purported to act for or on behalf of, directly or indirectly, a senior official of the government of the Russian Federation.” Also sanctioned were Rusal and the publicly traded holding company that controls it, En+. The sanctions caused Rusal’s share price to plummet by 50 percent and roiled the global aluminum market. Mr. Deripaska soon announced that he would relinquish control of Rusal and resigned from the boards of En+ and Rusal.