Same-day registration

Same-day registration procedures vary from state to state. Some states allow SDR from the early voting period through when the polls close onElection Day; others limit SDR’s use to either exclusively during the early-voting period or exclusively on Election Day. However, all states with SDR require voters who register and vote on the same day to provide proof of residency at the time of registration. This requirement can generally be satisfied with a driver’s license or a state-issued ID card, though some states let voters submit utility bills and other documents displaying their address. Voters who use SDR must also present identification at the time of registration or shortly thereafter. Some states that allow SDR require a photo ID, while others do not. The National Conference of State Legislatures provides a table of state-by-state identification and proof of residency requirements under SDR.  

The academic study of and discourse around SDR has focused on a few broad areas: voter turnout and voting accessibility, election administration, and partisanship effects.

Voter Turnout

Many political scientists have argued that SDR increases turnout. The theory underscoring this argument holds that registration requirements impose significant costs onto voters. In order to vote in an election, voters must: 

1. learn the deadlines and procedures concerning registration, 
2. appear in person or mail in the required documents prior to Election Day, and 
3. appear in person again or submit separate documents to cast their ballots. 

By eliminating the first two steps, proponents of the system claim, SDR makes it easier for voters to cast ballots (Wolfinger and Rosenstone 1980). Scholars have tested this theory using data from states that allow SDR, and many have concluded that SDR generally has a positive effect on turnout. While the size of this effect varies by study, scholars have generally reported gains of 3-6 points in turnout in SDR states (Brians and Grofman 2001; Knack 2001; Alvarez, Ansolabehere, and Wilson 2002; Burden and Neiheisel 2012; Leighley and Nagler 2014).  Researchers have pointed out that both registration and turnout were higher on average in SDR states than in non-SDR states (see Alvarez, Ansolabehere, and Wilson 2002). A 2022 study from the Tufts Center for Information & Research on Civic Learning and Engagement found that same-day voter registration increased turnout for voters aged 18-24 between between 3.1 and 7.3 percentage points. 

Some studies have disputed the conclusion that SDR increases turnout. Researchers who have taken this position have pointed out that earlier studies tended to compare turnout in states with SDR to states without SDR. However, because turnout varies between states for reasons other than SDR, research designs that focus on changes within a state may be more appropriate. When scholars have looked at changes in turnout within states to compare turnout before and after SDR, the effect of SDR appears much smaller (Keele and Minozzi 2013). 

Some scholarly research has found that SDR can change the composition of the electorate by making it easier for voters who have a difficult time meeting registration deadlines. A report from the Caltech/MIT Voting Technology Project found that SDR benefits voters who are younger, nonwhite, poorer, and less likely to have stable addresses (Alvarez, Ansolabehere, and Wilson 2002). Using Current Population Study data from several states, Craig Leonard Brians and Bernard Grofman find that SDR benefits low and middle-income voters most (Brians and Grofman 2001). The Institute for Responsive Government makes the case for same-day registration on the grounds it creates a “one-stop-shop” for election participation, where transient voters, college students, elderly adults, and individuals who have recently moved but are eligible to vote would not be faced with undue barriers to casting a ballot. 

Partisanship and Same-Day Registration 

Since its first recorded use in Maine in 1973, SDR has been a divisive topic: supporters make the case it increases voter turnout and aids election officials through technology advances, while opponents argue it is difficult to verify a voter’s identity, causes confusion for voters not aware of the process, and places a burden on election officials. These divisions tend to fall along age and party lines. 

Research on the partisan makeup of the electorate as a result of SDR is mixed. States which implemented EDR between 1980 and 1996 were about 5 percent more Democratic on average than non-EDR states, but states that passed EDR after 1996 were no different than other states in terms of partisan competition (Brians and Grofman 2001). In specific elections, however, there may be reason to believe that EDR does impact partisan competition. In their study of Wisconsin, for instance, Jacob Neiheisel and Barry Burden found that EDR was correlated with a decrease in the Democratic share of the two-party presidential vote (Burden and Neiheisel 2012). While not solely caused by same-day registration, North Carolina has experienced similar partisan trends from 2018-2026 as a result of changes in voter registration policy; more details can be found in our North Carolina State Report for the 2026 Elections Performance Central. 

Election Administration

Finally, there is some disagreement over the administrative costs of implementing SDR. Surveys of local election administrators have revealed that, while election officials broadly supported SDR, more than half of them believed that implementing EDR would increase the administrative burden placed on them (Burden, et al. 2009). However, surveys of the post-implementation costs of SDR suggest that, in many cases, the monetary costs of implementation were relatively low. Election officials could not always identify the specific, additional costs associated with SDR. 

Federal Legislation 

For the most part, states have full authority to set their own election deadlines and processes, aside from a few notable exceptions like those stipulated in the Help America Vote Act (HAVA)of 2002. HAVA requires states to provide provisional voting options, maintain a statewide voter registration database, and regularly update and upgrade voting equipment. Over the last decade, there have been numerous pieces of federal legislation introduced by both major parties that have sought to change the process of voter registration for federal elections. 

State Legislation 

Montana

In April 2021, Montana became the first state to eliminate SDR, when Governor Greg Gianforte signed H.B. 176 into law. This was after Montana voters had rejected a ballot measure six years before to end same-day registration. Organizations like the Montana Democratic Party, Native voting rights groups, local unions, and the ACLU filed lawsuits against H.B. 176 as early as September 2021. In March 2024, the Montana Supreme Court held that H.B. 176 was unconstitutional, and the case was not taken up by the U.S. Supreme Court. In May 2026, courts blocked further legislation that would have prohibited EDR for federal elections starting at 12 p.m. on Election Day. As of September 2026, SDR remains in effect for federal elections as the lawsuit continues to move through the courts.  

Illinois 

In October 2016, the 7th U.S. Circuit Court of Appeals reinstated the state’s same-day registration law after it was blocked by a lower court. The lower court had ruled the state’s Election Day registration law unconstitutional because it required counties with 100,000 or more residents to provide voters with an SDR option at polling places. Less populous counties were not subject to this requirement; opponents argued it would boost turnout to largely Democratic, urban areas without doing the same for Republican-leaning rural areas. SDR remains in effect in Illinois today so long as voters provide the required forms of voter ID. 

North Carolina

In 2023, North Carolina enacted S.B. 747, which made a number of changes to election procedures in the state, including changes to the verification of same-day voter registrations during the early voting period. Specifically, this legislation tightened the “notice and cure” process of verifying the address of same-day voter registrations. Under North Carolina state law, county boards of elections are required to mail an address verification card to same-day registrants if their address can’t be verified. S.B. 747 limits  county boards of elections to sending only one verification request card to a voter whose address cannot be verified; if this card is returned as undeliverable, the law requires board staff to remove the voter’s ballot from the official count and void their registration. After the law passed, voting rights advocates sued, arguing that  it would cancel voter registrations and invalidate ballots on the basis of one piece of undeliverable mail. A federal judge upheld the rule in March 2026 and it remains in effect. 

Websites

• National Conference of State Legislatures, Same Day Registration
• U.S. Vote Foundation, Election Dates and Deadlines
• Ballotpedia:  Arguments for and Against Same Day Voter Registration 
• MIT Election Data + Science Lab: Announcing Recipients of the Practice-Oriented Research to Improve Voter Registration and List Maintenance Grants

Readings

• R. Michael Alvarez, Stephen Ansolabehere, and Catherine H. Wilson. “Election Day Voter Registration in the United States: How One Step Voting Can Change the Composition of the American Electorate.” Caltech/MIT Voting Technology Project. Working Paper. 2002. 
• Craig Leonard Brians and Bernard Grofman. “Election Day Registration’s Effect on U.S. Voter Turnout.” Social Science Quarterly. Vol. 81, no. 1 (2001): 170-183.
• Barry Burden and Jacob R. Neiheisel. “The Impact of Election Day Registration on Voter Turnout and Election Outcomes.” American Politics Research. Vol. 40, no.4 (2012): 636-664
• Barry Burden, David T. Canon, Kenneth R. Mayer, and Donald P. Moynihan. “The Effects and Costs of Early Voting, Election Day Registration, and Same Day Registration in the 2008 Elections.” Report Presented to the Pew Charitable Trusts. December 21, 2009.
• Michael Hanmer. Discount Voting: Voter Registration Reforms and Their Effects. 2009. Cambridge: Cambridge University Press.
• Luke Keele and William Minozzi. “How Much Is Minnesota Like Wisconsin? Assumptions and Counterfactuals in Causal Inference with Observational Data.” Political Analysis. Vol. 21, no. 2 (2013): 193-216.
• Stephen Knack. “Election-Day Registration: The Second Wave.” American Politics Research. Vol 29, no. 1 (2001): 65-78.
• Jan E. Leighley and Jonathan Nagler. Who Votes Now?: Demographics, Issues, Inequality, and Turnout in the United States. 2014. Princeton: Princeton University Press.
• Raymond E. Wolfinger and Steven J. Rosenstone. Who Votes? 1980. New Haven: Yale University Press.