The Sensitivity of the U.S. Presidential Election to Coordinated Voter Relocation

U.S. presidential elections are determined by the Electoral College. In all but two states, a statewide winner-take-all system for electors can lead to decisive outcomes based on narrow victories in key states. Small groups of voters can significantly impact results, not only through turnout but also through a less-explored mechanism: the strategic relocation of a relatively small number of dedicated voters across state lines. The extent to which election outcomes are sensitive to such coordinated movements has not been thoroughly investigated. We introduce an analytical framework that integrates forecasting, simulation, and optimization to identify these pivotal voter shifts. Our findings show that small-scale relocations can meaningfully alter election probabilities under a range of parameter settings and polling data sources. Furthermore, we examine how the optimization-based recommendations align with actual election results, demonstrating that the suggested movements would have been beneficial in the 2024 U.S. presidential election—even when based on pre-election data. Given the remarkably small number of individuals required and the fact that electoral residency in many states can be established within about a month, our results have direct implications for policymaking and campaign strategy. Moreover, they highlight new opportunities for applying operations research methods to political science. History: Accepted by Alice E. Smith, Editor-in-Chief. Funding: This work was supported by an Natural Sciences and Engineering Research Council of Canada Discovery Grant. Supplemental Material: The software that supports the findings of this study is available within the paper and its Supplemental Information ( https://pubsonline.informs.org/doi/suppl/10.1287/ijoc.2024.0990 ) as well as from the IJOC GitHub software repository ( https://github.com/INFORMSJoC/2024.0990 ). The complete IJOC Software and Data Repository is available at https://informsjoc.github.io/ .