Cato Institute Tells U.S. Supreme Court the Federal Cannabis Ban Violates the Constitution

The amicus brief, submitted today, urges the Court to take up Canna Provisions v. Bondi and use it as the vehicle to overturn Gonzales v. Raich, the 2005 ruling that allowed federal prohibition to override state legalization. Cato’s 31-page brief lays out a direct challenge to the modern understanding of the Commerce Clause, arguing that the framers intended Congress to regulate interstate trade—not wholly local agriculture or manufacturing. The organization says that states like Massachusetts have built tightly sealed systems where every gram of marijuana is tracked “from seed to sale,” making the activity purely intrastate and therefore outside federal reach. By treating local marijuana businesses as part of interstate commerce, the filing argues, federal law collapses the constitutional divide between state and national authority.

According to Cato, the federal government’s position rests on legal theories that have drifted far from the Constitution’s original meaning. The brief argues that the Necessary and Proper Clause has been stretched to justify almost unlimited federal authority, and that the Court should now correct course. Cato frames the case as an opportunity to restore meaningful limits on federal power, warning that if Congress can criminalize Massachusetts-licensed marijuana businesses that operate entirely within state borders, it can regulate virtually anything.

The brief also highlights the stakes for personal liberty, echoing themes that have dominated recent federalism decisions. Cato argues that the Constitution’s structure—especially the division between state and federal authority—was designed to protect individual rights by preventing concentrated national power. Allowing the Controlled Substances Act to override state-regulated, intrastate marijuana activity, it says, erases that safeguard and effectively grants Congress a general police power that the framers rejected.

The filing arrives as the Supreme Court prepares to decide on December 15 whether it will take up the case, after multiple prominent legal groups signaled plans to submit supporting briefs. If the Court agrees to hear the challenge, it would mark the most significant federal marijuana case in two decades and could reshape the future of state legalization nationwide.