This chapter begins by arguing that rule of law exists in the probabilistic sense that dispassionate judges often reach similar legal conclusions for reasons that appear to be universal across humans. Well-designed legal systems amplify these probabilities so that majority opinion quickly hardens into clear rules. Still, the question remains why judges should elevate rule of law above their own personal preferences. The answer seems to be that the legal communities they serve value and reward predictable outcomes. Still, the strength of this incentive varies from one era to the next, and is almost always weaker in highly polarized eras. Politicians threats to pack or otherwise hamstring the Court can compromise its rulings. Despite this, the Court remains an indispensable check on Congress, the Executive Branch and, through the antitrust laws, private power.