I am used to prosecutors saying something to the effect that, “The law is clear, one must not do X, Y and Z.” After all, one cannot expect people to adhere to laws that are so vague that’s it is not even clear what sort of actions are in violation of the statute.

Here’s how this principle was described by Cornell Law School’s Legal Information Institute:

Void for vagueness


1) In criminal law, a declaration that a law is invalid because it is not sufficiently clear.  Laws are usually found void for vagueness if, after setting some requirement or punishment, the law does not specify what is required or what conduct is punishable.  For more information, see vagueness doctrine.

2) Under vagueness doctrine, a statute is also void for vagueness if a legislature’s delegation of authority to judges and/or administrators is so extensive that it would lead to arbitrary prosecutions.

3) In property law, a declaration that a deed or other instrument purporting to affect property rights is invalid because it lacks a sufficiently clear description of the property.

Thus I was surprised to see the new FTC chair cite the vagueness of antitrust law as a reason that she should have free rein to decide how the law is applied, that is, to engage in what Cornell Law School calls “arbitrary prosecutions”:

Shapiro has been critical of Khan’s approach to antitrust, particularly her view that enforcers focus too heavily on a so-called consumer welfare standard that emphasizes price as the main sign of a lack of competition. . . .

“Antitrust over the last few decades has become dependent on a particular type of economic theory,” Khan said. “The antitrust statutes are quite sparse. They are very general. There’s nothing in there about what econometric analysis to use. There’s been choices about what types of analysis to privilege.”

While the consumer welfare standard is not explicit in the law, it is surely more implicit than any other potential standard.  Khan seems to be saying that since we are not 100% certain that the framers of antitrust law wished to protect consumers from rapacious monopolists, it is perfectly acceptable for her to substitute some other policy goal, which is not written into the law.

And how were the companies that supposedly violated the law in the 2010s to know that Lisa Khan would be appointed FTC chair in 2021?  Should companies obey the law as it existed at the time they made decisions on company policy, or should they look into crystal balls and attempt to obey the law as it will be reinterpreted by unelected future bureaucrats?  And if the law is to change, shouldn’t it be Congress that decides how?

HT:  Tyler Cowen