Objectives The attitudes of gun owners and nongun owners appear more polarized in the last two decades. We posit that divisions between gun owners and nongun owners reflect emerging political identities, especially among gun owners. Methods Using data from the General Social Survey (1972–2012) we examine if and when this gun ownership divergence began to shape the political behavior of the two groups by analyzing voting patterns in presidential elections. Results We first observe that relative to conventional predictors of vote choice, gun ownership is important, reliable, and robust across election cycles. Since the 1970s, possessing a firearm increases the likelihood of voting for Republican candidates. Second, we find that the impact of gun ownership on the likelihood of voting for a Republican candidate increased across elections, reaching a level in 2012 nearly 50 percent higher than in 1972. The voting choices of gun owners and nonowners are therefore distinct and increasingly so over the past several decades. Conclusions Given the significant proportion of the electorate who owns guns, the prominence of guns in social and political culture, and the weight of gun lobbies in political affairs, the growing divide between gun owners and nonowners will likely continue and significantly impact electoral politics. Gun owners are developing a powerful political identity that rivals other groups' characteristics in its ability to predict voting behavior.