Justice Thomas, Joined by Justice Gorsuch, Argue for Broader Scope of Constitutional Ban on Ex Post Facto Laws

Brief excerpts from today's concurrence in Ellingburg v. U.S., though the whole opinion is worth a read:

I join the Court's opinion in full because it correctly applies our precedent. I write separately to clarify the foundation of that precedent. This Court's 1798 decision in Calder v. Bull established that the Ex Post Facto Clauses forbid only those retroactive laws that impose "punishment" for a "crime." Over the 228 years since Calder, the Court has struggled to articulate what it means for a law to impose punishment for a crime, and thus to be subject to the Ex Post Facto Clauses.

The Court's more recent precedents have implemented Calder through two multifactor tests that turn largely on whether the legislature labels the law as criminal or civil. But in 1798, "punishment" for a "crime" would have been understood to refer to any coercive penalty for a public wrong. Many laws that are nominally civil today would therefore have been subject to the Ex Post Facto Clauses under Calder. I would restore Calder's approach to the Ex Post Facto Clauses….

Calder's understanding secures Ex Post Facto Clause protection in a wide range of contexts involving nominally civil laws. Those contexts include civil proceedings seeking fines for public offenses. See, e.g., Army Corps of Engineers v. Hawkes Co. (2016) (describing "civil penalties of up to $37,500 for each day [the challenger] violated the Act"). They include enforcement proceedings brought by administrative agencies. See Axon Enterprise, Inc. v. FTC, 598 U. S. 175, 196 (2023) (Thomas, J., concurring) (describing the 20th-century rise of such proceedings). And they include municipal sanctions like speeding tickets. "If one were to commit a minor traffic offense at a time the offense was to be punished by a $25 fine, and the government were to then amend the statute and impose a fine of $1,000,000 dollars, it would be nonsensical to treat that fine as non-punitive simply because the offense was processed civilly." Brief for Professor Beth Colgan as Amicus Curiae. Because all of these offenses impose punishments for public wrongs, Calder would treat them all as subject to the Ex Post Facto Clauses.