Implementing voter ID: lessons from Missouri, USA

Many states have adopted laws requiring voters to present photo identification on Election Day. How are these laws implemented in a highly decentralized system of election administration? We report on a study of photo ID implementation in Missouri, focusing on the number of voters who check in at a polling place without photo identification during local and special elections held under the new law. These elections serve as early tests of the photo ID law and offer support for some hypotheses derived from implementation theory. We find evidence of uneven implementation of the photo ID requirement in Missouri. Local jurisdictions using electronic poll books checked in a much larger volume of voters without photo ID than jurisdictions using traditional paper poll books. Interviews with local officials suggest that voter and poll worker behaviour contribute to this pattern. Furthermore, other features, particularly jurisdiction size and the administrative and partisan structure of local officials, are associated with the number of voters who check in without photo identification. Therefore, the use of electronic poll books might overstate the number of voters lacking photo identification. In a decentralized system of election administration, it can be challenging to uniformly implement new voting requirements.