NYC and RCV: Changing Behavior, Not Outcomes
Despite the strong polling lead and prolific name recognition of former New York Gov. Andrew Cuomo, democratic socialist Zohran Mamdani secured a surprise victory in the Democratic primary for mayor of New York City. While pundits were quick to dissect the political consequences of the race, less has been said about the way in which the city’s election structure—ranked-choice voting (RCV)—left its mark on the race. Rather than shape who won, RCV helped shape how Mamdani won. He reached beyond his core supporters and created a coalition to help him reach majority support. While the oddities of New York’s system, including the lack of sore-loser laws, may have played a role, Mamdani’s approach to his campaign provides valuable evidence of how RCV may help change behavior without changing outcomes.
RCV is an electoral system that allows voters to rank candidates in order of preference—first, second, third, and so on. If no candidate receives a majority of first-choice votes, the candidate with the fewest votes is eliminated and their votes redistributed to the next-ranked choices on those ballots. This process continues in rounds until one candidate secures a majority. New York uses RCV in all of its primary and special elections.
A common criticism of RCV is that it benefits moderate candidates at the expense of more ideological candidates. However, Mamdani’s victory shows this is not the case. Rather than moderating his views or repositioning toward the political center, he embraced RCV’s incentives by building alliances with like-minded political allies. Look no further than his cross-endorsements with New York City Comptroller Brad Lander and former state assemblyman Michael Blake, fellow progressive Democrats who appealed to a complementary base of voters but with local connections that Mamdani lacked. This led to a largely positive campaign, with these candidates frequently appearing together on friendly terms—an approach that likely helped Mamdani earn second- and third-choice rankings from supporters of other progressive candidates.
Instead of chasing swing voters in the traditional sense, Mamdani built coalitions by expanding upon the traditional electorate. He engaged communities that had sparingly participated in city politics in the past. He invested heavily in outreach to younger, immigrant, and working-class voters, many of whom had not voted in previous primaries. This strategy enabled him to build a truly unique electoral coalition mobilized by his progressive vision. A spokesman for Mamdani’s chief rival, former Gov. Cuomo, explained that this approach expanded “the electorate in such a way that no turnout model or poll was able to capture,” as those accounted mostly for traditional voters. Mamdani’s achievement demonstrated how RCV can reward inclusive organizing and strategic alliance building, even for candidates with strongly defined ideological positions that lie well outside the mainstream.
This body of evidence points to largely positive effects from RCV, even in a contest where an ideologue secured victory. However, it is worth considering an external variable that may have amplified the incentives of RCV. In the vast majority of states, once a candidate loses a party primary, a “sore loser law” bars them from appearing on the general election ballot under any other party label or as an independent. These laws aim to preserve the finality of the primary process and prevent spoiler campaigns, but they also lock in primary results and limit voter choice in November.
New York State does not have a sore loser law, and its relatively open ballot access rules and allowance of multiple party lines give candidates much greater access to the ballot. As a result, someone who loses a major-party primary can still run in the general election on a third-party line—or as an independent—if they meet the petition requirements.
This legal structure became particularly relevant in the 2025 election cycle. Mamdani had to campaign in recognition that a narrow win in the Democratic primary might not guarantee the outcome and that the contest might spill over into the general election. This is now the case, as both Cuomo and incumbent Mayor Eric Adams have launched independent campaigns. In this environment, coalition building and appeals beyond an ideological core are all the more important—not only to gain ranked-choice support within the primary, but also to remain resilient in a potential multi-way contest in the general election. Therefore, the absence of a sore loser rule may have reinforced the incentives generally associated with RCV, pushing candidates to campaign inclusively.
The New York Democratic primary is just one contest, and more evidence is needed to isolate the impact of sore loser laws on campaign strategy in an RCV election. However, the race provides a useful case study for how RCV incentivizes better candidate behavior without undermining a fiercely ideological candidate in favor of a moderate or “establishment” candidate. While RCV is no silver bullet reform, it remains a viable option for conducting runoff elections in an efficient manner that allows candidates of all kinds to compete.