I haven’t read this paper yet, and I’m not going to be in NOLA due to Isaac, so I’ll let Dan Smith write for himself:

July 1, 2011, saw changes to the Florida state laws that govern the ways that individuals and nonpartisan community groups register voters in the state. Among the legal changes promulgated were new registration requirements for third-party groups like the League of Women Voters and a new oath, warning of prison time and fines, that voter registration agents had to sign before engaging in registration activities. Such changes raised the implicit costs that eligible Florida citizens faced when registering to vote, and we show, consistent with this logic, that voter registrations across Florida in late 2011 dropped precipitously compared to registrations in late 2007. This pattern is evident among registrants in general, among registrants age 21 and younger, and among the number of individuals who registered as Democrats and the number of who registered as Republicans. Beyond the aforementioned, mid-2011 changes in voter registration regulations, all of which were products of a piece of Florida state legislation known as House Bill 1355, we know of no credible, alternative explanations for our findings. Our results thus show how restrictions on
the way that third-party organizations register voters can have tangible effects on actual registrations and, given that registration prior to an election is a civic necessity in Florida, can affect electoral participation.