  I provide an axiomatization of stochastic utility over two periods, stating
testable necessary and sufficient conditions under which an agent's choice
behavior under exogenous menu selection can be modeled by a pair of random
utility functions. Although static random utility is characterized by a single
axiom, Block-Marschak nonnegativity, I demonstrate that an additional notion of
marginal consistency is needed for the two-period axiomatization. In
particular, when each period's choice set has size three, I restate the
characterization using the simpler axiom of stochastic regularity. I conclude
by stating several corollaries, including an axiomatization of stochastic
utility with full support and an axiomatization of n-period stochastic utility.
