City of Chicago v. Morales

In City of Chicago v. Morales, 527 U.S. 41 (1999), the U.S. Supreme Court held as unconstitutionally vague an anti-loitering ordinance that defined loitering as remaining in place with "no apparent purpose," finding that standard "inherently subjective because its application depends on whether some purpose is 'apparent' to the officer on the scene."