The opinion was written by Justice Stevens, with Justice Alito writing a concurring opinion, joined by the Chief Justice, and Justice Scalia dissenting, joined by Justice Thomas.
Petitioner Padilla, a lawful permanent resident of the United States for over 40 years, faces deportation after pleading guilty to drug distribution charges in Kentucky. In postconviction proceedings, he claims that his counsel not only failed to advise him of this consequence before he entered the plea, but also told him not to worry about deportation since he had lived in this country so long. He alleges that he would have gone to trial had he not received this incorrect advice. The Kentucky Supreme Court denied Padilla postconviction relief on the ground that the Sixth Amendment’s effective assistance-of-counsel guarantee does not protect defendants from erroneous deportation advice because deportation is merely a "collateral" consequence of a conviction.
Held: Because counsel must inform a client whether his plea carries a risk of deportation, Padilla has sufficiently alleged that his counsel was constitutionally deficient. Whether he is entitled to relief depends on whether he has been prejudiced, a matter not addressed here.