CA Proposition 39: Voter ID Measure

The national fight over voting rights has landed in California, where Proposition 39 seeks to amend the state constitution to require government-issued identification at the polls and the last four digits of a unique government-issued identifying number on mail-in ballots. Prop. 39 would also require the state to verify current voter registration lists, regularly audit compliance with the new rules, and pass laws to ensure their implementation.

For supporters, Prop. 39 is a "commonsense" method of preventing voter fraud by verifying voters' identities and reforming a system they view as lax and inefficient. Opponents say it would create needless bureaucratic hurdles to voting, especially for marginalized groups.

The measure was filed in July 2025 by state Assemblymember Carl DeMaio, a Republican from San Diego, and state Sen. Tony Strickland, a Republican from Orange County. DeMaio framed Prop. 39 as a bipartisan attempt to “[keep] voting easy and simple and improve how we verify who is voting to restore public trust and confidence in our elections.”

Under current California law, anyone registering to vote must provide a California driver’s license or state ID number if they have one, or the last four digits of their Social Security number if they do not. These are checked against DMV or Social Security records.

However, people without either can still register to vote, and are assigned an identifying number. Applicants must affirm U.S. citizenship under penalty of perjury, though applicants do not need to submit a passport, birth certificate, or naturalization certificate in most cases. Most voters do not have to show identification at the polls, with the exception of certain first-time federal election voters who registered by mail or online without having their identifying information verified.

In 2024, Gov. Gavin Newsom signed a law prohibiting any jurisdiction in California from adopting a local law requiring voters to present ID before voting. If Prop. 39 is approved, it would override that prohibition.

Currently, mail-in ballots must be postmarked by Election Day and received within seven days afterward. Election officials compare the signature on each return envelope with signatures in the voter’s registration record, though an exact match is not required. If a ballot is missing a signature or officials determine the signature does not match, they must notify the voter and provide an opportunity to correct the problem before the ballot is rejected.

According to an October 2024 Public Policy Institute of California poll, 63 percent of California likely voters expressed a “great deal” or “quite a lot” of confidence in the system for casting and counting votes in California. In a May 2026 Berkeley IGS poll, 65 percent of California registered voters said they were confident local officials would conduct the June primary fairly and securely and count votes accurately. In the same poll, 31 percent said they were not.

If Prop. 39 passes, voters casting ballots in person would be required to present government-issued identification, though the measure does not explicitly require photo ID. On mail-in ballots, voters would need to provide the last four digits of a government-issued ID number matching the one on their registration record. The state would provide a voter ID card at no charge if requested by an eligible voter.

Ballots could only be counted after officials verified the identity of the voter. The measure would also require state and county officials to make their best efforts to verify citizen attestations and annually report the percentage of each county’s voter rolls whose citizenship had been verified. The state auditor would be required to audit state and county compliance each odd-numbered year and publish the findings. Prop. 39 would also require the state legislature to pass laws pertaining to the implementation of the new regulations.

According to the state’s nonpartisan Legislative Analyst’s Office, Prop. 39 could cost state and local governments from tens of millions to the low hundreds of millions of dollars each year to implement the new regulations.

Supporters say these stricter measures are necessary to prevent fraud and duplicate registrations. Supporters also note that some form of voter ID laws are present in 36 states and many other democracies, though exact requirements vary greatly.

“We’re not trying to reinvent the wheel,” Strickland, a Republican from Huntington Beach, said in an interview with Patch. “And again, we’re one of only 14 states that doesn’t require ID to vote, and I think people need to have faith in election outcomes. Our democracy doesn’t work if people don’t have faith in those election outcomes.”

Yet opponents, including Democratic gubernatorial candidate Xavier Becerra and numerous progressive groups, say that Prop. 39 would make voting unnecessarily difficult, and could lead to eligible ballots being dismissed.

“For California, we already require citizenship and ID verification at the point of registration. Our number one priority for California is to ensure that there are not burdens for eligible citizens to vote, and this is an unnecessary additional burden to voters," Cynthia Valencia, a senior policy advocate and organizer for the ACLU of Southern California, said in an interview with Patch. “We believe and know, based off of evidence, that California’s elections are already secure, that there are sufficient safeguards. Prop. 39 doesn’t make them safer. It is only creating new barriers and hurdles to voting, harming voters.”

In August 2025, the California Research Bureau reviewed documented individual election fraud cases, including fraudulent registrations, voting on behalf of a dead person, and attempted double voting. Several resulted in convictions or guilty or no-contest pleas, although election safeguards prevented some fraudulent votes from being counted. According to the Senate Election Committee’s summary, grand jury reviews examining elections from 2020-2024 in 14 California counties found no evidence of voter fraud.

Valencia and many other opponents of the law feel that it creates an unnecessary burden that could disenfranchise vulnerable populations. Anita Chabria, a columnist for the Los Angeles Times, told the story of an 18-year-old under the alias of Sofia trying to get a government-issued identification. She did not have the bills, pay stubs, or student records required by the DMV. She wanted to order a certified birth certificate, but needed proof of identity to order it.

Chabria vouched for Sofia’s identity before a notary. Sofia then applied for a credit card and obtained a letter from a nonprofit, providing enough documentation for the DMV to issue her a REAL ID. She had to move before it arrived and tried to arrange mail forwarding with the post office, but they required ID. The Real ID was lost in transit.

“That means Sofia is one of thousands of Californians, born and raised in the Golden State, who lack official identification because it’s not as easy to obtain it as some want you to believe,” Chabria wrote in The Times. “And because she lacks it, she could be prevented from voting if Proposition 39 is passed, even though she is a legal citizen with every right to have her ballot counted, and California already has a system in place to ensure only citizens vote.”

Strickland countered that most services require forms of ID. “You need ID for government assistance,” he said. “You need an ID to get medicine, and you need ID to get on a plane. If they really feel that way, then they should remove the requirement for IDs for getting government assistance.”

Opponents of the bill, however, are worried that not only would the amendment make it harder to vote, it could result in eligible ballots being discarded.

“[Prop. 39] is going to designate a very specific identification number used for voting. So then people are going to have to remember that number, to know which form of ID they designated, and then perfectly match those last four digits every single time they vote,” Valencia said. “So either write it on their mail-in ballot or make sure that they have that ID when they go to their polling center. And that just creates so many ways and hoops that people are going to have to jump through that could easily get tripped up if they write the wrong digits, if it’s illegible when they write on the mail-in ballot. It’s just creating more layers that could lead to legitimate and eligible ballots being thrown out.”

Prop. 39 does not specify whether officials would be required to notify voters of missing or mismatched ID information and give them an opportunity to correct it, as current law requires. Further legislation could establish such a process.

Polling on the issue remains varied. A poll from Sept. 4-10 from the Public Policy Institute of California shows that 43 percent of Californians surveyed support the measure, while 55 percent oppose, with a margin of error of 3.8 percentage points. Meanwhile, an April 2026 poll from the U.C. Berkeley Institute of Governmental Studies found 56percent in support and 39 percent in opposition. Other polls, like a May 2026 PPIC poll, found 49 percent in support and 51 percent in opposition.

Three PACs in support of the measure have reported about $17.1 million in contributions, according to Ballotpedia. At least nine billionaires have contributed to the fundraising committee Californians for Voter ID. The top donor is Republican Richard Uihlein, who contributed $4 million, according to Ballotpedia.

Californians for Voting Rights, a PAC that opposes the initiative, reported more than $294,000 in contributions, according to Ballotpedia.