Christopher Devine, University of Dayton As presumptive Democratic presidential nominee Joe Biden gets set to pick his vice presidential candidate, here’s a reality check: Running mates have very little direct effect on voters. When people go to the polls, they are primarily expressing a preference for the presidential candidate, not the second person on the ticket. In our new book, “Do Running Mates Matter?,” my collaborator Kyle Kopko and I analyze half a century of political science survey data to examine what effect a running mate has on the success of presidential candidates. In general, voters are very unlikely to choose a presidential ticket simply because they like or dislike the second-in-command.read more