Ashcroft v. al-Kidd

Holding: (1) The objectively reasonable arrest and detention of a material witness pursuant to a validly obtained warrant cannot be challenged as unconstitutional on the ground that the arresting authority allegedly had an improper motive; and (2) because former Attorney General Ashcroft did not violate clearly established law, he is entitled to qualified immunity. (Kagan, J., recused).

Plain English Holding: Former Attorney General Ashcroft cannot be sued for violating the Fourth Amendment rights of people who were arrested and held in custody under warrants intended to ensure that they appeared as witnesses at someone else’s trial, even when they argue that they were actually detained so that law enforcement officials could investigate them or to prevent them from committing future crimes.

Judgment: Reversed and remanded, 8-0, in an opinion by Justice Scalia on May 31, 2011. Justice Kennedy filed a concurring opinion, which Justices Ginsburg, Breyer, and Sotomayor joined in part. Justice Ginsburg filed an opinion concurring in the judgment, which Justices Breyer and Sotomayor joined. Justice Sotomayor also filed an opinion concurring in the judgment, which Justices Ginsburg and Breyer joined. (Kagan, J., recused)