Same-day voter registration—where a voter can both register and vote on Election Day—improves democracy in the United States by making it easier for people to vote. Same-day voter registration promotes greater participation: states with this policy tend to have higher turnout than states with onerous registration deadlines. This reform has a notable, positive impact on young and minority voters as well as individuals who move frequently. It also helps to maintain more accurate voter rolls. Twenty states and the District of Columbia already or will soon offer same-day registration, and research shows widespread public support for the practice. With improved resources and better technology, the remaining states can and should offer voters increased access to the ballot through same-day registration.