Messrs. Epstein and Loyola make a compelling case that the court should return Chevron to its rightful place—as an eminent U.S. petroleum company, not a rule of thumb by which courts shirk their responsibility to declare what statutes mean when confronted with ambiguous words. In an effort to secure majority support for legislation, lawmakers often insert imprecise and facially inoffensive language into statutes, knowing that like-minded agency officials will clarify the meaning, to their party's liking, when regulations are later promulgated. But the best reading of statutes should always prevail over self-serving interpretations that unelected executive branch officials would prefer to read into them. Administrations change and "plausible readings" of statutory terms can be retrofitted, one administration to the next, to achieve vastly different policy goals. A stamp of certainty by the courts promotes confidence on the part of people and industries affected by federal statutes that what's lawful conduct one year will remain so after New Year's Eve.