For decades antitrust agencies, courts, and scholars have debated whether Section 7 of the Clayton Act permits an efficiency defense, in which merging firms can argue that enhanced efficiencies from the merger show that it does not reduce competition. However, the Supreme Court’s recent establishment of the “major questions doctrine,” which enforces or re-enforces a textualist reading of regulatory statues, undermines proponents of the efficiency defense, because the Clayton Act does not clearly and explicitly contain an efficiency defense. The “major questions doctrine” essentially acts as textualism on steroids,” writes Robert H. Lande.