The Justice Department is right to defend as essential the century-old ban on direct corporate contributions to political candidates for federal office. In a brief to the United States Court of Appeals for the Fourth Circuit, the lawyers challenge a wrongheaded ruling by Judge James Cacheris of Virginia, arguing that the ban serves the government’s strong interest in preventing political corruption.

In the Citizens United case, the Supreme Court said corporations and other organizations could make unlimited independent expenditures in political campaigns. But the court said it was not overturning the ban on direct corporate contributions to candidates’ campaigns.

Flouting that precedent, Judge Cacheris ruled that the “logic” of “Citizens United requires that corporations and individuals be afforded equal rights to political speech, unqualified.” He also flouted a 2003 Supreme Court case upholding the ban on direct corporate donations. Judge Cacheris has no basis for rejecting those two decisions, which bind the lower courts until the Supreme Court overturns them.

As the government contends, he was wrong in ruling that contributions from corporations “pose no greater risk of corruption or its appearance” than those from individuals if they stay within the $2,500 limit that individuals are allowed to donate. A corporation is “easy and inexpensive to form,” the government’s brief says, and it can create “a web of subsidiaries and affiliates” and “multiply its capacity to make contributions.”