GTE Sylvania's actions appeared to be illegal per se under the rule established in United States v. Arnold, Schwinn & Co., 388 U.S. 365 (1967), where the Court similarly considered a territorial restriction on the sale of a product.

Noting that "per se rules of illegality are appropriate only when they relate to conduct that is manifestly anticompetitive," 433 U.S., at 49–50, the court concluded that GTE's behavior transgressed the Sherman Act only if it was an unreasonable restraint of trade that would diminish competition and promote inefficiency.

The initial ground was broken by economist George McGee, who reanalyzed the biggest antitrust ruling in history, the Supreme Court's split up of Standard Oil in 1911.

McGee's view is now widely criticized, by lawyers Christopher Leslie, Elizabeth Granitz, Benjamin Klein, economists James Dalton, Louis Esposito, and historians Ron Chernow, Daniel Yergin.

Other Chicago economists who influenced antitrust debates in ways that narrowed and limited its legal basis include Ronald Coase, Gary Becker, and George Stigler.