This paper provides the first estimate of the effect of door-to-door canvassing on actual electoral outcomes, via a countrywide experiment embedded in François Hollande Banerjee et al. 2013), and political discussions are commonly seen as the healthy expression of a functioning democracy. To the extent that democracy revolves around the deliberation and transformation of people's preferences, rather than the simple aggregation of their votes, discussion may actually be as important a condition of democracy as the electoral participation of all citizens (Habermas 1996; Elster 1998). The importance people attach to political discussions is illustrated by DellaVigna et al.'s (2017) result that many of us vote in order to later be able "to tell others."But discussions also affect future political behavior. In their pioneering study on the 1940 US presidential election, Lazarsfeld et al. (1944) find that most voters got their information about the candidates from family members, friends, and colleagues, rather than from the media (see also Gentzkow and Shapiro 2011). Nickerson (2008) and Bond et al. (2012) provide direct evidence of the diffusion of voter turnout off-and online in more recent elections. While diffusion can be driven