ACLU attorneys contend that without a warrant, such tracking violates the Constitutional amendment against unreasonable searches. The ACLU is scheduled to square off with government lawyers on Tuesday in federal appeals court in Philadelphia.
According to legal briefs, the government will argue that authorities shouldn't need a warrant if they have probable cause to believe something criminal is afoot.
The case before the Third Circuit Court of Appeals involves three brothers suspected of robbing pharmacies in the Philadelphia area.
