Also known as: retroactive application · retroactivity of laws · retroactive laws · ex post facto · retroactivity
Written by attorneys · grounded in primary & secondary sources — see below
The application of a newly enacted statute to conduct or events that occurred before the statute took effect.
Ralph Richardson operated a business under rules that permitted certain financial arrangements. After a new state statute reclassified those arrangements as criminal, prosecutors charged him for the earlier transactions. The court dismissed the charges because the statute could not reach conduct completed before its enactment.
Ronald Reed completed an alleged offense in 1995, after which the statute of limitations ran. A later statute extended the period and prosecutors filed charges. The court held the extension invalid because it reopened a time-barred case and altered the legal consequences of past conduct.
Select any source to read its text and confirm it supports the definition.
Rajesh Rao engaged in conduct that federal law did not criminalize at the time. Congress later enacted a statute that reached the earlier conduct and imposed penalties. The court refused to apply the statute because it operated retroactively to increase punishment for completed acts.
Rosa Ruiz entered a guilty plea relying on existing sentencing rules. A subsequent statute altered the consequences of that plea. The court declined to apply the new statute retroactively because it would change the legal effect of the completed plea.
Roland Rhodes committed a capital offense under an earlier statute later held invalid. A new sentencing statute was enacted before trial. The court permitted the new statute because it did not increase the likelihood of the death penalty compared with the prior framework.
Renee Rogers faced charges before a military commission under existing procedures. Congress later altered the procedures and the government sought to apply them to the pending case. The court rejected the retroactive application because the change would alter the rules governing the completed conduct.
Retroactive application violates the Ex Post Facto Clause when the statute criminalizes past conduct, increases punishment, or alters the quantum of evidence needed for conviction. The prohibition applies to both federal and state legislatures. Courts examine whether the new law disadvantages the defendant by changing the legal consequences of completed acts.
No. Retroactive civil legislation satisfies due process if supported by a legitimate legislative purpose and rational means. Short periods of retroactivity used to correct tax code errors or close loopholes are routinely upheld. The inquiry focuses on whether the retroactive reach is modest and serves a public purpose.
A landowner who obtains a permit and makes substantial good-faith expenditures in reliance on existing zoning acquires a vested right to complete the project. Later ordinances cannot be applied retroactively to halt that project. Courts protect the owner's reasonable investment-backed expectations once substantial reliance has occurred.
No. Extending a statute of limitations after it has already expired and then applying the extension to past conduct violates the Ex Post Facto Clause. The change retroactively alters the legal sufficiency of the evidence and reopens the possibility of punishment for completed acts.
…ample funds to secure one, the expedient of giving a warning is too simple and the rights involved too important to engage in ex post facto inquiries into financial ability when there is any doubt at all on that score. [^maj-44]: If an individual indicates his desire to remain silent, but has an attorney present, there may be…