Additional, Rigorous Evidence that Voter Identification Laws Suppress Voting

The historic 2020 election has re-opened debates about election procedures. Newly implemented measures have encountered partisan legal challenges, and unsubstantiated allegations of voter fraud have reached a fever pitch. In the election’s wake, policymakers and scholars will likely face pressing questions about how to ensure the integrity of elections and access to the vote. As lawmakers propose new rounds of changes, we argue for informed attention to controversial state-level voter identification (ID) policies.

ID laws mandate that a potential voter show an acceptable form of identification before casting a ballot in person—and some proposed new rules would extend such rules to mail ballots. The results of our systematic study based on the nationally-representative Current Population Survey (CPS) add to the growing body of evidence that relatively strict voter ID policies suppress electoral turnout. Indeed, our evidence shows that ID policies are associated with lower levels of voting across all of the major racial and ethnic groups. This fact should concern lawmakers of all backgrounds across partisan divides.

The Spread of Voter ID Policies

Voter ID policies have been implemented by state legislatures dominated by both Republicans and Democrats—although they are recently associated with Republicans, especially in electorally competitive states. Such policies are frequently justified by pointing to unsubstantiated fears of "voter fraud,” including fears about potential illegal in-person voting, despite a lack of evidence that this occurs in any substantial way.  

Although official investigations—including by the FBI and other non-partisan organizations—have debunked the myth of systematic voter fraud in American elections, voter ID laws and proposals have not only spread but have become more restrictive. During the 2000 election, fourteen states had voter ID laws, and the number of states with such measures increased to thirty-two by the 2016 election, and to thirty-five by November 2020. State ID laws specify various acceptable types of IDs—ranging from utility bills to state-issued photo-ID cards. Over recent years, more and more states require harder to obtain IDs, states with stricter rules do not allow a citizen to vote without the required identification.

Do Voter ID Policies Suppress Voting?

Critics of ID policies have raised concerns that they can suppress voting and place disparate burdens on the economically-disadvantaged, the elderly, and on racial and ethnic minorities. Regardless of their partisan or political intent, we sought to investigate how voter ID policies impact actual electoral turnout. Existing studies of the effect of voter ID policies have generated vigorous debate. Our study addresses the debates by analyzing the Current Population Survey (CPS) and by including data stretching from 2000—just before ID requirements were starting to spread throughout the country—through 2016, by which time a variety of ID policies were in place.

We found that voter identification laws are associated with lower levels of self-reported voter turnout, especially in states requiring photo-IDs for verification. Controlling for a host of individual and state-level variables known to influence voting, we found that ID laws decreased the predicted probability of turnout between 1.6% and 3.9% percent, depending on the restrictiveness of the ID rules. Importantly, we found that voter ID policies discourage voting by eligible adults in all four major racial/ethnic groups (Black, white, Latino and Asian-American). Additional evidence suggests that the negative effects of strict ID policies are strongest for Latino citizens.

We also analyzed the effects of newly implemented ID laws in Wisconsin and Mississippi by comparing turnout in those states to turnout in two states other states, Michigan and West Virginia, that did not change their electoral laws between 2012 and 2016. We calculated that implementing strict photo voter ID policies lowered the predicted probability of voting by 4.1%, lending support to our overall findings across all states.

Policies Can Expand or Contract the Franchise in Future Elections

Clearly, state-level policies can encourage or suppress electoral participation. Voter ID policies are part of a constellation of measures that create more restrictive voting environments. Along with ID laws, other practices—such as voter registration purges, felon disenfranchisement, and proof of citizenship laws—are often adopted under the guise of protecting electoral integrity. Regardless of their intent, we found that strict versions of these policies have dampened electoral turnout for voters across all major racial and ethnic categories. What is more, ten of the fifteen “swing states” with important sway in the Electoral College have potentially suppressive voter identification laws. By contrast, other policies can help expand access to the vote—especially automatic voter registration, universal mail-in voting policies, election-day registration, and extensive early voting policies.

The number of Americans potentially affected by ID laws is increasing. For the 2020 election, thirty-five states had such policies in place. If voter ID laws reduce the probability of voting by just a few percentage points, they may swing election results even at a national level. It is essential that individual citizens be aware of the potential consequences of voter identification laws long in-advance of elections, especially in places that require hard-to-obtain state IDs. Policymakers need to be aware that ID policies risk excluding citizens of all backgrounds and persuasions from exercising franchise, a bedrock of democracy.