Doe v. Ashcroft is a significant legal case decided in 2003 that challenged the constitutionality of certain provisions of the USA PATRIOT Act, particularly those related to surveillance and the collection of personal information without a warrant. The case involved concerns over privacy rights and civil liberties, highlighting tensions between national security measures and individual freedoms during the post-9/11 era. This ruling set a precedent for future discussions about government powers and individual rights in the context of security legislation.