Cornell University law professor Michael C. Dorf argues that if President Trump were to pardon himself, that action itself would not cause a constitutional crisis, but other actions Trump has already taken have already placed us far along a road to a constitutional crisis. Dorf defines a constitutional crisis in terms of three types first articulated by Sanford Levinson and Jack Balkin in a 2009 law review article, and Dorf proposes a fourth type characterized by defiance of unwritten norms that are not themselves legal obligations but that undergird the constitutional system as a whole.