## Facts

- A witness observed a car driving erratically, swerving off the road and stopping in a field without injury or property damage; the driver walked away.
- Police arrived minutes later, learned the driver appeared very intoxicated or ill, checked the vehicle registration, and went to the registrant’s nearby home.
- Around 9 p.m., officers entered the home without a warrant and arrested the suspect, who was found naked in bed, for first-offense operating while intoxicated (OWI).
- Under Wisconsin law at the time, first-offense OWI was a civil, noncriminal violation punishable only by a forfeiture fine, with no imprisonment.
- At the station, the arrestee refused a breath test; Wisconsin law permitted license revocation after a hearing, and treated refusal as reasonable if the underlying arrest was unlawful.
- The trial court upheld the arrest and suspended the license; the state intermediate appellate court vacated for lack of exigent circumstances; the state supreme court reinstated on an exigency theory.

## Issues

1. Whether the Fourth Amendment permits warrantless nighttime entry into a home to arrest a suspect for a civil, nonjailable traffic offense based on asserted exigent circumstances.
2. Whether “hot pursuit” or dissipation of blood-alcohol evidence constituted exigent circumstances on these facts sufficient to overcome the presumption against warrantless home entry.

## Decision

- The Supreme Court reversed, holding the warrantless nighttime home entry and arrest violated the Fourth Amendment.
- The Court ruled that, absent exigent circumstances, police may not enter a home without a warrant to arrest for a civil, nonjailable traffic offense.
- The Court rejected “hot pursuit” because there was no immediate or continuous pursuit from the scene; officers arrived after the driver left and later went to the home.
- The Court found dissipation of blood-alcohol evidence did not justify the entry given the minor, nonjailable nature of the offense under state law.
- The Court emphasized the State bore the burden to show exigent circumstances overcoming the presumption of unreasonableness attached to warrantless home entries.

## Legal Principles

- Warrantless entry into a home is presumptively unreasonable under the Fourth Amendment; the government must prove exigent circumstances to justify it.
- In evaluating exigent circumstances for home entry, the gravity of the underlying offense is a central factor.
- When there is probable cause to believe only a minor offense has been committed, applying the exigent-circumstances exception to justify home entry should rarely be permitted.
- “Hot pursuit” requires immediate or continuous pursuit from the scene; a delayed approach to a suspect’s residence does not qualify.
- Potential destruction of evidence may support exigency in some settings, but it is generally insufficient to justify nonconsensual home entry to arrest for an extremely minor, nonjailable offense, especially where the State has chosen to treat the conduct as civil.

## Conclusion

The Court held that the Fourth Amendment’s special protection for the home prohibits warrantless nighttime entry to arrest for a civil, nonjailable OWI offense, and that neither a non-continuous “pursuit” nor routine dissipation of blood-alcohol evidence supplied exigent circumstances adequate to overcome the warrant requirement.


Welsh v. Wisconsin, 466 U.S. 740 (1984)