This article explores the particular form of "public gambling" that emerged at spectator sporting events in early America. The piece begins by describing the origins and function of public gambling in the late colonial period, which arose from efforts to cultivate business and political "friends" rather than a desire for winning bets and money. After the Revolution, this networking function became less connected to close personal friendships, and more closely tied to an impersonal, expanding, and lucrative horse breeding industry, in which bettors used public wagers to express confidence in a bloodline and thus raise its value. Yet the article concludes by showing how the depersonalization of public gambling at racetracks coincided with its adaptation by politicians eager to use the older association with "friendship" to connect with a widening electorate of white men who associated citizenship with bold and successful economic risk-taking. In sum, then, this essay argues that not all gambling was motivated by individualistic greed or marked by class distinction, as much of the current literature suggests. Instead, gambling was a diverse set of practices, and public gambling reveals how the act was used to build extensive vertical networks of "friends" that helped cohere the white male republic.