Also known as: ex post facto · ex-post-facto rule · ex post facto laws · retroactive criminal law prohibition
Written by attorneys — see sources below.
A constitutional prohibition barring legislatures from enacting criminal laws that retroactively criminalize conduct, increase punishment for past acts, or alter rules of evidence to the defendant's disadvantage. The rule ensures fair notice by preventing new or harsher penalties from attaching to completed conduct.
Ella Emerson completed a series of sales transactions in State A before any statute addressed them. State A later passed a law criminalizing those exact transactions and imposing prison terms. Ella faces prosecution under the new statute for her prior conduct.
Emanuel Escobar's alleged offense occurred years earlier and the statute of limitations had already expired. The legislature then extended the limitations period and applied it retroactively to his case. Prosecutors reopen the matter and seek to convict him under the revived window.
Elena Estrada engaged in conduct that was lawful when performed. Congress later enacts a statute making that same conduct a federal crime and directs that it apply to all prior instances. Federal authorities indict her solely on the basis of her pre-enactment actions.
Ethan Evans published a work under an existing copyright term. Congress later lengthens the term and applies the extension to already-published works. Ethan claims the change retroactively alters his legal position in a manner forbidden by the ex post facto rule.
In 1998 Congress enacted the Copyright Term Extension Act, which extended the duration of all federal copyrights by twenty years. For works created by identified natural persons the new term runs from creation until seventy years after the author's death. For anonymous works, pseudonymous works, and works made for hire the term is ninety-five years from publication or one hundred twenty years from creation, whichever expires first. The statute applied these extended terms both to copyrights already in existence and to works created after its effective date. Petitioners are individuals and businesses whose products or services build on copyrighted works that have gone into the public domain. They filed suit in the United States District Court for the District of Columbia seeking a declaration that the extension of existing copyrights exceeded Congress's power under the Copyright Clause and violated the First Amendment. On cross-motions for judgment on the pleadings the district court entered judgment for the Attorney General. The Court of Appeals for the District of Columbia Circuit affirmed. A majority of the panel upheld the statute against both challenges, while Judge Sentelle dissented in part on the Copyright Clause issue. The Supreme Court granted certiorari to address whether the extension of existing copyrights exceeds Congress's power under the Copyright Clause and whether the extension violates the First Amendment.
View caseEric Espinoza distributed materials under the prevailing obscenity test at the time. A later Supreme Court decision announces a new standard and prosecutors attempt to apply it to his earlier distribution. Eric objects that the new test cannot govern his completed conduct.
The appellant conducted a mass mailing campaign advertising the sale of illustrated books and a film described as adult material. After a jury trial he was convicted under California Penal Code § 311.2(a) for knowingly distributing obscene matter based on the mailing of five unsolicited advertising brochures to a Newport Beach restaurant. The brochures contained explicit pictures and drawings depicting sexual activity and genitals. This case was tried on the theory that California's obscenity statute incorporated the tripartite Memoirs test and the jury was instructed to apply contemporary community standards of the State of California. Both parties at trial assumed the community standards were those of the State of California; defense counsel did not object to the state's expert testimony on community standards or to the judge's instruction. Appellant raised for the first time on appeal the contention that application of state rather than national standards violated the First and Fourteenth Amendments. The judgment of the Appellate Department of the Superior Court, Orange County, California, came before the Supreme Court of the United States for review as part of a group of obscenity cases in which the Court re-examined the standards for identifying obscene material that may be regulated by the States.
View caseEwan Eckhart held a legal status under the law in force when he acted. A subsequent decision recharacterizes that status and imposes new disabilities on the prior conduct. Ewan contends the change violates the ex post facto rule by punishing him for acts lawful at the time.
Dred Scott, along with his wife Harriet and their two children Eliza and Lizzie, was held as a slave by the defendant John F. A. Sandford in the State of Missouri. Scott initiated an action in the Circuit Court of the United States for the District of Missouri asserting his and his family's right to freedom. The declaration averred that Scott was a citizen of Missouri and the defendant a citizen of New York to establish diversity jurisdiction. The defendant responded with a plea in abatement asserting that the court lacked jurisdiction because Scott was not a citizen of Missouri. Scott was a negro of African descent whose ancestors were of pure African blood and had been brought into the country and sold as slaves. Scott demurred to this plea. The Circuit Court overruled the plea and required the defendant to answer over. The defendant then filed pleas in bar. After a trial on the merits the jury returned a verdict in favor of the defendant, leading to judgment for him. Scott then prosecuted a writ of error to the Supreme Court. The underlying facts showed that Scott had been the slave of Dr. Emerson, a surgeon in the United States Army. In 1834 Emerson took Scott from Missouri to Rock Island in Illinois, where he held him as a slave until 1836. Emerson then removed Scott to Fort Snelling in the Territory of Upper Louisiana north of thirty-six degrees thirty minutes north latitude, holding him there until 1838. Harriet, originally the slave of Major Taliaferro, was also brought to Fort Snelling and sold to Emerson. Scott and Harriet were married at Fort Snelling in 1836 with Emerson's consent, and their children were born there or during the return journey. In 1838 Emerson brought the family back to Missouri, where they resided until Emerson sold them to Sandford. The case reached the Supreme Court after two arguments. The Court ordered reargument on some of the points due to differences of opinion among the justices and the importance of the questions involved.
View caseThe rule bars legislatures from making conduct criminal after the fact, increasing punishment for completed acts, or changing evidentiary rules to make conviction easier. These changes all operate retroactively on past conduct.
Supporting sources
The prohibition applies to criminal or penal legislation. Civil regulatory measures generally fall outside its scope unless they are so punitive in purpose or effect that they function as punishment.
Supporting sources
Yes. Extending a limitations period after it has already expired and applying the extension to revive a time-barred prosecution retroactively alters the legal consequences of past conduct and violates the clause.
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No. The rule targets only retroactive criminal punishment. Prospective changes and most civil measures remain permissible even when they attach new consequences to past facts.
Supporting sources
…a measure was "necessary and proper" to the discharge of its substantive legislative authority, pass a bill of attainder or ex post facto law contrary to the prohibitions contained in § 9 of Art. I. No more may it vest in itself, or in its officers, the authority to appoint officers of the United States when the Appointments…