Any analysis of the president's ability to influence citizen opinions is fundamentally tied to question about the attentiveness of the public, the stability of individual opinions, how citizens acquire and process information, and the impact of information on opinion change. Insofar as these questions are concerned, the absence of individual-level analyses creates a gap in the presidential approval literature. The aggregate-level studies, which constitute the bulk of the literature, are valuable for identifying the events and conditions which influence the time path of public support. They do not, however, provide direct evidence about how individuals decide to maintain or change their evaluations of presidential performance. Quite obviously, such evidence is critical to any debate about the president's ability to influence public support. The research reported herein addresses this deficiency by formulating and evaluating an individual-level model that explains citizen evaluations of the president. Using a cybernetic approach to human decision making, we build upon Neustadt's characterization of the president's public and formulate a series of design principles. A model based upon these principles is operationalized and tested using panel data collected for the Center for Political Studies. A series of simulations are performed to examine the implications of the model. The results are then used to reflect upon the debate over the president's ability to influence public support.