For 45 years, the Freedom of Information of Act has invigorated American democracy by obliging the executive branch to make public a splendid range of documents. It serves the people’s right to know, while leaving out data whose disclosure could be harmful.

The law’s “exemption 7,” about facts gathered for law enforcement, omits records whose release could be “an unwarranted invasion of personal privacy.” Until now courts have unanimously agreed its purpose is to protect individuals. Last month, the Supreme Court heard arguments about a case in which the Court of Appeals for the Third Circuit, in Philadelphia, decided “personal privacy” includes the privacy of corporations.

Federal Communications Commission v. AT&T addresses whether AT&T can prevent the F.C.C. from releasing documents about the company’s overbilling of the government. If the justices supported that interpretation, they would wreak havoc on the Freedom of Information Act. Fortunately, there’s little risk of that.

The appeals court’s ruling rests on faulty analysis. It found that the exemption’s text settled the matter by using the phrase “personal privacy.” “After all,” the court said, “ ‘personal’ is the adjectival form of ‘person,’ and F.O.I.A. defines ‘person’ to include a corporation.”