Ex Tunc

Ex tunc is a legal term that means a decision or action is effective retroactively from a particular point in time. It is often contrasted with 'ex nunc', which means that an action is effective from the time of the ruling forward.

The term originates from Latin, commonly used in the context of legal doctrines and philosophies to delineate the temporal effects of judicial decisions. Its use can be traced back to Roman law, where the implications of time frames in legal decisions were critical.

In contemporary legal practice, ex tunc is used in various contexts, including contract law and tort law, to determine the validity or enforceability of contracts that are deemed voidable from the outset. For instance, if a contract is declared void ex tunc, it is treated as if it never legally existed.

• A court ruling that invalidates a marriage affects the legal status of that marriage upon its initial transaction, not just from the date of the ruling.
• A contract declared void due to misrepresentation is treated as null from the time it was created.

• Claflin v. Walsh, 160 U.S. 103 (1895)