Johnson was convicted in 1994 of a federal drug offense, and received a sentence enhancement because of his prior Georgia convictions. In 1996, AEDPA was passed, which imposed a one-year deadline to challenge a federal sentence. In 1998, Johnson sought habeas relief in Georgia. The state court vacated the prior Georgia convictions because Johnson had not waived the right to counsel in those cases. Johnson then sought to vacate the federal enhancement based on the Georgia convictions. The appellate court found his challenge untimely. The United States Supreme Court affirmed. In a case in which a prisoner collaterally attacks his sentence on the ground that a state court conviction used to enhance that sentence has been vacated, the one year limitations period begins to run when the petitioner receives notice of the order vacating the prior conviction, provided that he has sought it with due diligence in state court after entry of judgment in the federal case in which the sentence was enhanced. The state court order vacating his prior conviction is a matter of “fact” supporting his claim, discovery of which triggers the refreshed one year limitation period. However, here, Johnson’s challenge was not timely because he waited more than three years after his conviction to file a state habeas petition, which is not due diligence.