D drove past a California highway patrol officer listening to loud music with his windows down and repeatedly honking his horn. The officer began to tail D, and soon afterward turned on his overhead lights to signal that D should pull over. D was only about a hundred feet (some four-seconds drive) from his home. D continued to his driveway and entered his attached garage. The officer followed D and began questioning him. Observing signs of intoxication, the officer put D through field sobriety tests. Lange did not do well, and a later blood test showed that his blood-alcohol content was more than three times the legal limit. D was charged with the misdemeanor of driving under the influence of alcohol, plus a (lower-level) noise infraction. D moved to suppress all evidence obtained after the officer entered his garage, arguing that the warrantless entry had violated the Fourth Amendment. P contends that the officer had probable cause to arrest for the misdemeanor of failing to comply with a police signal. P argued that the pursuit of a suspected misdemeanant always qualifies as an exigent circumstance authorizing a warrantless home entry. The Superior Court denied D’s motion, and the appellate division affirmed. It held that D’s “failure to immediately pull over” when the officer flashed his lights created probable cause to arrest him for a misdemeanor. And a misdemeanor suspect, the court stated, could “not defeat an arrest which has been set in motion in a public place” by “retreating into” a house or other “private place.” It held an “officer’s ‘hot pursuit’ into the house to prevent the suspect from frustrating the arrest” is always permissible under the exigent circumstances “exception to the warrant requirement.” Courts are divided over whether the Fourth Amendment always permits an officer to enter a home without a warrant in pursuit of a fleeing misdemeanor suspect. Some courts have adopted such a categorical rule, while others have required a case-specific showing of exigency. California abandoned its defense of the categorical rule. The Supreme Court granted certiorari.