NEW : Justices Samuel Alito , Clarence Thomas dissent . NEW : Justice Antonin Scalia joins the majority opinion in a case that could have major implications for campaign finance law and other areas of government regulation. Ruling aims to shrink disparity between powder cocaine and crack sentences .
NEW : Justices Samuel Alito , Clarence Thomas dissent . NEW : Justice Ginsburg writes , `` law says nothing about appropriate sentences '' Supreme Court : Judges may impose shorter prison terms for crack cocaine . Ruling aims to shrink disparity between powder cocaine and crack sentences .