Universal suffrage is a cornerstone of democratic governance. As levels of criminal punishment have risen in the United States, however, an ever-larger number of citizens have lost the right to vote. The authors ask whether felon disenfranchisement constitutes a meaningful reversal of the extension of voting rights by considering its political impact. Data from legal sources, election studies, and inmate surveys are examined to consider two counterfactual conditions: (1) whether removing disenfranchisement restrictions alters the outcomes of past U.S. Senate and presidential elections, and (2) whether applying contemporary rates of disenfranchisement to prior elections affects their outcomes. Because felons are drawn disproportionately from the ranks of racial minorities and the poor, disenfranchisement laws tend to take more votes from Democratic than from Republican candidates. Analysis shows that felon disenfranchisement played a decisive role in U.S. Senate elections in recent years. Moreover, at least one Republican presidential victory would have been reversed if former felons had been allowed to vote, and at least one Democratic presidential victory would have been jeopardized had contemporary rates of disenfranchisement prevailed during that time.