Election Day Registration (EDR), which allows eligible voters to register and cast a ballot on Election Day, is a reform that reduces the unnecessary disfranchisement of eligible voters that may be caused by arbitrary registration deadlines.

For many years, six states (Idaho, Maine, Minnesota, New Hampshire, Wisconsin, and Wyoming) have offered EDR, and since the 2004 presidential election, two additional states — Montana and Iowa — have joined their ranks, while a third, North Carolina, has enacted an analogous measure allowing Same Day Registration at early voting sites. As a result of these recent changes, the 2008 presidential election may see unprecedented use of EDR by American voters.