A federal appeals court is being asked to decide whether to place limits on the government's ability to search electronic devices at airports.
The American Civil Liberties Union argues that searches should not be conducted without a warrant or probable cause of a crime.
The appeals court was to hear arguments Thursday in the case of a Turkish national convicted of trying to illegally smuggle weapons parts to Turkey.
Hamza Kolsuz was arrested at Washington Dulles International Airport in Virginia after agents found weapons parts in his luggage.
During his trial, a judge denied Kolsuz's motion to suppress evidence found during a forensic search of his phone.
The ACLU says significant privacy interests are at stake because of the vast amount of personal information stored on electronic devices.