 Points about ratification in decision problems clarify points about equilibrium in game theory because in games of strategy a player’s choice often furnishes evidence about other players’ choices. Decision theory underlies game theory because a game’s solution identifies rational choices in the decision problems the game creates for the players. Solutions to games distinguish correlation and causation, as do decision principles. Because in simultaneous-move games two agent’s strategies may be correlated but not related as cause and effect, solutions to such games do not have the same properties as solutions to sequential games. Causal decision theory attends to distinctions on which solutions to games depend. It supports game theory’s account of interactive decisions. Joyce and Gibbard (2016) describe the role of ratification in game theory, and Stalnaker (2018) describes causal decision theory’s place in game theory.