The case—Citizens United v. Federal Election Commission—involves a 90-minute documentary produced by Citizens United, a small nonprofit advocacy corporation. “Hillary: The Movie” examines the record, policies and character of the former New York senator, now Secretary of State, Hillary Rodham Clinton. The documentary was set to be broadcast during Mrs. Clinton’s presidential primary campaign. But the broadcast was banned when the Federal Election Commission declared that the broadcast would violate the 2002 McCain-Feingold campaign finance law.

The government defends this restriction by saying that corporations and unions are uniquely capable of amassing great wealth and must therefore be prevented from overwhelming the voices of others during an election. Relying on a 1990 Supreme Court decision (Austin v. Michigan State Chamber of Commerce), the government characterizes this threat as a “type of corruption” on the peculiar theory that such expenditures do not “reflect actual public support for the political ideas espoused by corporations.” Therefore, the government reasons, corporate expenditures “distort” the political process and must be banned.

In crafting McCain-Feingold, Congress acted without proof that such expenditures have any distorting effect on elections. And it responded to a nonproblem with a sledgehammer rather than a scalpel. The current ban on candidate-related speech is not limited to big corporations or powerful unions. It prohibits election advocacy by all unions and all corporations, regardless of size. It even criminalizes speech by nonprofit advocacy corporations such as Citizens United and the ACLU, which cannot conceivably distort or corrupt the political process.