The high court's 7-2 ruling came Wednesday in the case of Roselva Chaidez.
The Supreme Court ruled in 2010 that immigrants have a constitutional right to be told by their lawyers whether pleading guilty to a crime could lead to their deportation. Chaidez had already been convicted for mail fraud and was in a deportation proceeding. She then asked the courts to allow her to take advantage of the new ruling.
Justice Elena Kagan wrote that the 2010 ruling was a new rule, so it doesn't apply to convictions that came before. Justices Sonia Sotomayor and Ruth Bader Ginsburg dissented.