Mayfield v. United States (2007)Issue: Brandon Mayfield, an American attorney wrongfully detained by the FBI due to a fingerprinting error linked to the 2004 Madrid train bombings, sued the government, claiming that the surveillance and searches conducted under the PATRIOT Act violated his Fourth Amendment rights.

Outcome: The U.S. District Court for the District of Oregon ruled that certain provisions of the PATRIOT Act were unconstitutional, particularly regarding the government’s use of surveillance and searches without a warrant. The government later settled with Mayfield and issued a formal apology.

Impact: While the case did not lead to broader changes in the PATRIOT Act, it highlighted potential constitutional violations under the Fourth Amendment.