How Arizona’s Proof of Citizenship Law Works

Bringing an Arizona-style proof of citizenship law to other states requires policymakers to be attentive to costs, complexity, and implementation challenges. Arizona’s law heavily depends on a number of technological capabilities that most states currently lack. As other states consider replicating Arizona’s requirement that voter registration applicants provide proof of citizenship, policymakers must ensure that their state is ready to take on the complicated logistics of verifying documentation.

Very few Arizona voters actually provide physical documents while registering to vote. Election officials use existing state and federal databases to verify citizenship for the vast majority of applicants.

Below is a description of how Arizona’s proof of citizenship law actually works. At the end of the document is an implementation checklist for policymakers in other states who are considering adopting an Arizona-style law and would like a roadmap to help ensure that the state is ready to tackle logistical challenges.

How Arizona Voter Registrants Prove Citizenship

Because Arizona has required and retained proof of citizenship or authorized presence for driver’s licenses since 1996, most registrants are verified using Arizona Motor Vehicle Division records. Arizona’s state voter registration application has a box for registrants to enter their Arizona driver’s license numbers. Election officials work collaboratively with the MVD to allow election officials to verify that the applicant’s driver’s license number matches the record of the voter and that the customer provided documentary proof of citizenship during their original MVD transaction.

But not all registrants have Arizona driver’s licenses, or provided documentary proof of citizenship during their MVD transaction.¹ Applicants whose citizenship cannot be verified through MVD records can still avoid submitting copies of physical documents if they provide any of the following numbers directly on the state’s voter registration application: Alien Registration Number, Naturalization Certificate Number, Citizenship Certificate Number, Indian Census Number, Bureau of Indian Affairs Number, Tribal Treaty Card Number, or Tribal Enrollment Number.

Only the small percentage of applicants who lack any of the above numbers are required to submit physical documents. Those documents must be mailed to the county election official and can include copies of any of the following:

• A U.S. Birth Certificate. If the name on the birth certificate differs from the applicant’s current legal name — for instance, if the registrant is among the 80% of women who change last names upon marriage² — the registrant must submit additional supporting documents such as a marriage certificate.
• A U.S. Passport
• U.S. Naturalization Documents Tribal Certificate of Indian Blood or Tribal or Bureau of Indian Affairs Affidavit of Birth
• Tribal Certificate of Indian Blood or Tribal or Bureau of Indian Affairs Affidavit of Birth

Only a small percentage of registrants successfully submit documents to election officials.

Verifying Citizenship Using Existing Data

Verifying citizenship requires access to a number of databases. In addition to state MVD records, Arizona has tried or has considered trying the below databases, although many have drawbacks that limit their usefulness:

• State Birth Certificate Database. Election officials can work with their state’s vital records agency to match a registrant to their birth certificate if they were born in the state. The matching is based on name and date of birth, so it can be error-prone — especially for common names like John Smith. It also is more complicated for the roughly 80% of married women who changed their names upon marriage, and does not help registrants born in other states. Lastly, many states don’t permit vital records to be freely shared even among other state agencies, so policymakers need to ensure that state law allows election officials to access the data.
• NAPHSIS (National Association for Public Health Statistics and Information Systems). Election officials can use this database to match registrants with birth certificates from other U.S. states outside their home state, although not all states choose not to participate (for example, Texas). There is no single national database of U.S.-issued birth certificates. Access to the NAPHSIS database is expensive. As of early 2025, it typically costs more than $5 per record lookup, plus any fees imposed by the issuing state. Like other birth certificate records, the data fields are generally limited to name and date of birth, which is not robust enough for election officials to have high confidence in matches.
• Federal SAVE system. Election officials can manually search this USCIS tool to verify immigration status and confirm status of naturalized citizens. The searches are fairly expensive: in the 2025 fiscal year non-federal agencies are charged $1.50 per record, but the rate will more than double to $3.10 per transaction by 2028.³
• The United States Department of State holds U.S. Passport databases. Although various state election officials have requested access to this database for purposes of verifying citizenship, the federal government has not responded.

When working with any external database, election officials should carefully communicate with the keepers of the data to ensure that they understand each relevant data field and are relying on it appropriately. They should also communicate regularly to understand any changes in the data or how it is kept.

What Happens if all These Efforts Still Fail to Establish Citizenship

Federal voter registration requires a sworn statement of citizenship, which is at odds with Arizona’s stricter proof requirement. This creates a dual-registration system, where individuals who fail to provide citizenship documentation can still vote in federal elections but are ineligible for state and local contests. Managing this bifurcated system imposes administrative burdens on election officials, who must track and process two distinct voter rolls, along with multiple sets of ballot styles, voter instructions, educational materials, and so on. Arizona spends millions annually on extra administrative costs that result from its dual-track registration system.

Roughly 6.3% Arizona voters are currently on the federal-only list. Nearly 85% of Arizona’s federal-only registrants received an Arizona’s driver’s license prior to 1996. This cohort is mostly between the ages of 45-65 and are disproportionately registered Republicans or unaffiliated.⁴ The remaining 15% of federal-only voters largely consists of college students.⁵ These voters are placed on a federal-only list indefinitely, but can cure up to and including Election Day and receive a full ballot.

Policymakers wishing to implement an Arizona-style citizenship law should provide ample resources to ensure that election administrators are fully prepared for the complexities of a dual-track election system, and are ready to maintain separate voter rolls, ballot styles, educational materials, and poll worker procedures for federal-only voters. Election officials also must provide training to poll workers and staff to handle physical documents brought in by federal-only voters who wish to cure their registrations and vote a full ballot.

Data Privacy Considerations

Arizona election officials must be attentive to data privacy considerations that result from handling large numbers of sensitive personal documents. Although registrants currently only have an option of mailing physical copies of documents, election officials must have protocols in place to handle and store such sensitive documents.

Secure online document portals are a more secure, accessible option. The Arizona secretary of state is working to establish an online portal that would allow registrants to securely upload copies of documents or a text program to verify documents (similar to Text2Cure⁶), but has faced technical difficulties and lack of funding.

Policymakers in other states should ensure that a secure online submission portal is available and well funded to safeguard personally identifying voter data. Proof of citizenship laws should also make clear that citizenship information is to be used solely for voter registration purposes. Election officials lack training and resources to properly track and store physical copies of personally identifying documents.

Has Arizona’s Law Been Successful?

Even with a sophisticated implementation infrastructure in place, the law has resulted in high-profile errors, expensive litigation, and costly implementation challenges.

In the fall of 2024, Arizona election officials discovered an MVD data error that resulted in the discovery that nearly 218,000 registered voters had been incorrectly recorded as providing proof of citizenship when they had not. The issue generated negative press and required heroic efforts by secretary of state and MVD staff to fix the problem for as many voters as possible prior to the November 2024 general election. Fully resolving the issue could take months or even years. Both county and state Arizona election officials must provide affected individuals with notice, a clear opportunity to provide proof of citizenship, and a place to ask questions. They must also prescribe a set of detailed procedures to ensure that election officials can efficiently and securely process the expected influx of documents and questions, and to deal with any other expected logistical challenges that arise.

Court challenges have frequently resulted in sudden changes to implementation procedures, sometimes immediately before an election, which has imposed significant administrative challenges.⁷ The state has spent well over $2 million in legal fees while defending its law in court.⁸

The proof of citizenship law currently blocks roughly 6.3% of Arizona voters from fully participating in elections. Nearly 85% of Arizona’s federal-only registrants received an Arizona’s driver’s license prior to 1996 and are largely registered Republicans and Independents, and the remaining 15% are largely college students. When registering, all attested under penalty of perjury that they are U.S. citizens eligible to vote. There is no evidence that any meaningful percentage of these nearly 250,000 voters are not U.S. citizens.

Implementation Checklist

Anyone wishing to enact an Arizona-style proof of citizenship requirement should first ensure that the following are in place.

• A clear statement that election officials will automatically initiate citizenship confirmation using existing state and federal databases. Individuals only need to provide physical documentation if the database check is inconclusive.
• The state’s motor vehicle licensing agency should clearly record whether applicants provided proof of citizenship during their transaction.
• Election officials must have an established, secure method of accessing MVD citizenship records, and communicate regularly about any changes to data fields.
• Election officials should have access to the following databases and appropriate funds to pay for any subscription or record search fees.
• State vital records agency to access state-issued birth certificates.
• SAVE
• NAPHSIS (National Association for Public Health Statistics and Information Systems)
• To the extent permitted, states should access databases made available by the federal government like the Federal Data Services Hub or U.S. Passport lists through the Department of State.
• The state’s chief election officer should maintain an online portal that allows registrants in pending status to securely upload proof of citizenship or request help.
• Laws should ensure robust privacy and security of personal data, and should prohibit election officials from using state or federal data for any purpose other than confirming eligibility to participate in U.S. elections. Personally identifying information provided to election officials for the purpose of citizenship verification should not be discoverable under state public records laws.
• Policymakers should clearly state the process for registrants whose database checks are inconclusive. The best practice is to move registrants to a pending confirmation status and offer an opportunity for them to cure. Registrants should be able to cure by providing documents online, by mail, or in person.

¹ For example, well over 200,000 registered Arizona voters received their driver’s license before proof of citizenship requirements were in place. Thousands more naturalized after receiving a driver’s license.
² https://www.pewresearch.org/short-reads/2023/09/07/about-eight-in-ten-women-in-opposite-sex-marriages-say-they-took-their-husbands-last-name/
³https://www.uscis.gov/save/about-save/transaction-charges
⁴ As of September 2024, this cohort was 36% Republicans, 28% Democrats, and 32% unaffiliated or other. https://azsos.gov/news/849
⁵otebeat, Arizona’s federal-only voters are concentrated on college campuses, data show, available at
https://www.votebeat.org/arizona/2023/12/18/arizona-federal-only-voters-concentrated-college-campuses-proof-of-citizenship/
⁶Txt2Cure uses multiple layers of authentication to allow voters to cure signatures on mail ballots. More info here: https://www.coloradosos.gov/pubs/elections/FAQs/TXT2Cure.html
⁷ https://azsos.gov/news/849; see also https://www.cbsnews.com/news/arizona-supreme-court-ruling-citizenship-documents-voting-state-local-races-database-error/
⁸ Arizona paid more than $2 million to plaintiffs after the U.S. Supreme Court partially struck down its law. Litigation over the law’s implementation continues to this day, 21 years after its 2004 enactment. See, e.g. https://www.documentcloud.org/documents/25169592-decisionorder-5273666-0/