There I was, just standing on the street minding my own business, when a cop stopped and demanded my identification. Am I required to give it to him?
Technically no, though you may be required to state your name or risk spending time in jail. In Hiibel v. Nevada (2004), the U.S. Supreme Court upheld a Nevada court ruling that police may request identity in cases where officers have a reasonable suspicion of wrongdoing. According to Privacy International, 21 states have laws that allow police officers to conduct a "Terry stop," named for a landmark 1968 Terry v. Ohio decision that allowed police to frisk individuals if they have a reasonable suspicion the person is involved in criminal activity or poses a threat to them. In a Terry stop, an officer can ask for your identity if he or she can explain to a judge later what you were suspected of doing wrong. (Critics of the Terry decision claim it has been used as a pretext for police harassment, particularly of minorities—as in the classic traffic stop for "driving while black.") However, the Supreme Court ruled in Hiibel that you're not required to flash an ID, just to give your correct name. Otherwise, you generally have the right to remain silent—at least until the Supreme Court decides to revisit the Miranda decision.