Encouraging Crossover Voting in the 2024 Presidential Primary

Will voters participate in the opposing party’s presidential primary to prevent ananti-democratic candidate from winning that party’s nomination? We investigated thisquestion by partnering with an advocacy group to conduct a first-of-its-kind, large,preregistered field experiment (N = 83,800), in the lead-up to the 2024 Republicanpresidential primary in New Hampshire. We find that a specialized get-out-the-voteintervention increases turnout in the Republican primary among a subset of undeclaredvoters who are modeled as Democrats. Our treatment increased Republican Primaryturnout in this sample by 1.6 percentage points while reducing turnout in the Demo-cratic Primary by 0.5 percentage points. In previous surveys conducted by our partnerorganization, self-identified Democrats supported the pro-democratic candidate at 86percent, meaning this increased Republican primary turnout implies increased supportfor the pro-democratic candidate. Consistent with preregistered expectations, we findthat higher levels of contact were modestly more effective in generating turnout, andtreatment was more effective for more educated voters. We argue that encouragementsto crossover vote are an important avenue for bolstering sophisticated, pro-democracybehavior in the electorate, especially among informed voters and some subsets of par-tisans.