Objectives: The attitudes of gun owners and non-gun owners appear more polarized in the last two decades. We posit that divisions between gun owners and non-gun 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 non-owners are therefore distinct and increasingly so over the past several decades. Conclusions: Given the significant proportion of the electorate that 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 non-owners will likely continue and significantly impact electoral politics. Gun owners are developing a powerful political identity that rivals other group’s characteristics in its ability to predict voting behavior.