In Starbucks Corp. v. McKinney, an eight-Justice majority trimmed the power of the National Labor Relations Board (NLRB) to enjoin employers pending administrative enforcement proceedings. The decision broke with the Third, Fifth, and Sixth Circuits, which had required preliminary injunctions to issue upon a showing that the NLRB's legal theory was "substantial and not frivolous." Rejecting that government-friendly rule, the Court instead agreed with the Fourth, Seventh, Eighth, and Ninth Circuits that injunctions enforcing the labor statute are subject to judicial scrutiny under the traditional four-factor test—which requires a demonstration of irreparable harm and likelihood of success on the merits. The decision will surely blunt what had been a potent weapon in the NLRB's enforcement arsenal.