"The Dictator’s Dilemma: to Punish or to Assist? Plan Failures and Interventions under Stalin" is no. 51 in the PERSA series. The paper is by Andrei Markevich, Marie Curie Fellow in the Department of Economics, University of Warwick. The paper is about the problem that arises when a dictator issues an order, but the order is not carried out. The dictator does not know whether the order failed because the agent behaved opportunistically, or because his order contained some mistake. Imperfect information creates his dilemma: whether to punish the agent, or assist her or both. This paper models the dictator’s intervention when an order fails. The analysis links the dictator’s coercive policy with the softness of budget constraints. The model is verified against the history of Stalin’s dictatorship, using statistical evidence extracted from the formerly secret records of the Communist Party's "control commission." Originally received on 20 September 2007, the paper is freely available on line from www.warwick.ac.uk/go/persa.