John D. Ashcroft v. Abdullah Al-Kidd

Summary

The Supreme Court held that an objectively reasonable arrest and detention of a material witness pursuant to a validly obtained warrant cannot be challenged as unconstitutional on the basis of allegations that the arresting authority had an improper motive, because Fourth Amendment reasonableness is predominantly an objective inquiry and the purpose inquiry recognized in checkpoint cases is confined to suspicionless seizures under a general scheme without individualized suspicion. The Court further held that former Attorney General Ashcroft was entitled to qualified immunity even assuming his alleged pretextual-detention policy violated the Fourth Amendment, since no judicial opinion had clearly established such a rule in 2003; the Court therefore did not reach absolute immunity. Justice Kennedy concurred in full, stressing the holding's limits and the deference owed national officeholders; Justices Ginsburg and Sotomayor concurred only in the judgment, objecting that the Court unnecessarily resolved the novel Fourth Amendment question on a questionable valid-warrant premise.