This article presents a model of individuals' party identification that contrasts with previous models. Past models, with the few recent exceptions noted, assume a hierarchical relationship either from identification to other aspects of political behavior, such as the perception and evaluation of issues and candidates, or from these behaviors to party identifications. The model discussed here places party within a dynamic concept of the electoral process and tests several hypotheses about factors producing changes in identifications. The first factor, consistent with the spatial-type issue voting models, estimates the effects of the relative proximity of each party to the individual's own policy preferences. Second, we examine the effect of the actual voting decision on subsequent identifications, with the expectation that if votes differ from previous identifications, there is a resulting shift in partisanship. Finally, we examine the hypothesis that identifications become less susceptible to change as people age and accumulate political experience. When combined with other research, the results indicate a model of the electoral process in which party identifications are both influenced by circumstances specific to each election and influence other behaviors. This nonrecursive model has a number of implications for the development and evolution of individual and aggregate partisanship. These implications are discussed at the end of the article.