The U.S. Supreme Court, ruling unanimously for Facebook, on Thursday significantly undercut the federal law banning robocalls. But Justice Samuel Alito Jr. had broader concerns.

Justice Sonia Sotomayor, writing for the court, said the definition of “autodialers” in the 1991 Telephone Consumer Protection Act did not apply to Facebook because the technology used by social media giant to send text messages to plaintiff Noah Duguid did not use a “random or sequential number generator” as required by the federal law.