The traditional literature on Mexico's formerly hegemonic party, the PRI, notes the importance of the ‘informal rules of the game' in determining outcomes, such as who will be the PRI's presidential candidate. This article argues that the onset of electoral competition allowed weaker actors within the party to strengthen their position by reforming the statutes in order to give them decision-making power previously denied them. However, this was a difficult process. President Salinas was able to overturn statutory reforms, while President Zedillo was not. Now that the PRI has lost the presidential elections, internal mechanisms of distributing selective benefits become even more important because of the loss of the omnipotent president who once exacted cooperation from all actors within the party and the regime.