In United States v. Vaneaton the Ninth Circuit held that police did not violate the Fourth Amendment to the United States Constitution by making a warrantless arrest of a suspect who answered his door in response to their knock. The majority distinguished the case from the United States Supreme Court's holding in Payton v. New York, which ordinarily requires police to obtain a warrant before arresting a suspect inside his or her dwelling. Instead, the court found that the police did not need a warrant to arrest the suspect, even though he stood within the identifiable threshold of the doorway, because he voluntarily exposed himself to the warrantless arrest by freely opening his door. In so holding, the Ninth Circuit ignored the firm line drawn in Payton by allowing a warrantless entry into a dwelling so long as police use no coercion and announce the arrest before stepping inside.
After United States v. Vaneaton, Does Payton v. New York Prevent Police from Making Warrantless Routine Arrests Inside the Home?, 26 Golden Gate U. L. Rev.