In 1970, the U.S. Supreme Court gave its approval to a special type of guilty plea, one in which a criminal defendant maintains his innocence while at the same time accepting a plea deal from the prosecution. Those "Alford pleas," named after the case Alford v. North Carolina, are permissible when a defendant believes it is in his best interest and, the Supreme Court added, when there is "a factual basis for the plea."