Treating a friend to voter registration in a Divided America.

As partisanship strengthens in the United States, unaffiliated voter registration is also increasing. We conducted an original survey experiment to understand voter registration choices among registered voters in Florida and North Carolina, two states with substantial shares of unaffiliated registrants and persistent partisan polarization, but with differing primary participation rules. Institutionally, Florida holds closed primaries where only those registered with a political party may participate in the respective primary for that party. North Carolina holds semi-closed primaries that allow those not registered with a political party (i.e., unaffiliated registrants) to vote in party primary elections. The results of our experiment demonstrate that institutional context matters. Specifically, informing respondents of primary participation rules shapes voter registration recommendations. Among registrants who identify as independents, exposure to Florida's closed primary rule causes them to be more likely to recommend party registration, whereas awareness of the semi-closed North Carolina primary rule makes independents and partisans more likely to advise unaffiliated registration. However, in the absence of information explaining rules for primary participation, respondents are more likely to suggest that their friend register in alignment with their own political identity. In summary, our study provides valuable insights into how registration choices are conditioned by political identities and exposure to treatments that emphasize political conditions and primary participation rules.