PROP 39: The California Voter ID Initiative
Summary
A sound election system has to do two things simultaneously: Prevent voter fraud while ensuring that every eligible vote is counted. Proposition 39 is arguably an attempt to improve electoral confidence while minimizing negative effects on ballot access.
Proposition 39 requires that voters provide either state-issued identification to vote in person or the last four digits of a government-issued identification number to vote by mail-in ballot, similar to many other states. It also requires that elections officials publish regular eligibility audits of voter rolls. Lastly, it mandates that California create an alternate state ID card so that those who don’t have other forms of ID, like a driver’s license, are able to vote.
Given that over 80 percent of California voters make use of mail-in ballots, Proposition 39’s greatest impacts will be on mail-in voting rather than in-person voting. California’s recent shift to all-mail elections has vastly expanded the ease of voting and, as a result, voter participation. It also has opened up a new, more rewarding avenue for voter fraud. There is no credible proof of widespread or systematic election fraud in California. Yet instances of fraud have been uncovered, and the increase of mail-in voting has coincided with decreasing confidence in the honesty of elections.
Because California’s existing election systems already requires elections officials to contact voters—by mail, email, and phone—to “cure” their mail-in ballot of any deficiencies and allows voters twenty-two days after Election Day to do so, expanding identification requirements does not seem likely to substantially inhibit valid votes from being counted.
Realistically, there is an inherent trade-off between election legitimacy and making voting easy. This measure effectively asks voters whether increased legitimacy is worth making voting slightly more difficult.
Quick Facts
- Official ballot title: The original title was “Establishes Additional Voter Identification and Citizenship Verification Requirements” but this was changed by the California attorney general to “Prohibits Citizens from Voting Unless They Present Government-Issued Identification.” Ballot measure proponents challenged the new name as misleading, but the deputy attorney general argued that the title is only misleading if read in isolation. The Sacramento Superior Court ruled the changed title and summary were “sufficient.”
- Measure’s own name: The California Voter ID Initiative (AG No. 25-0007A1)
- Type: Initiated constitutional amendment
- A vote YES means: Voters must show government-issued ID to vote in person or provide the last four digits of a government ID number on their mail-in ballot envelopes. The state must offer a free voter ID card and conduct regular audits of voter rolls to verify eligibility and citizenship.
- A vote NO means: California keeps its current system, which asks for no ID at the polls and verifies mail ballots by signature match.
- Full legal text: Initiative 25-0007A1, Office of the Attorney General (PDF)
- LAO analysis: Ballot analysis of Initiative 25-0007
1. What would it do?
More than two-thirds of states require a voter to provide identification to receive a ballot, and recent national polls by the Pew Research Center, Rasmussen Reports, and Gallup show that over 75 percent of US adults support photo ID requirements to vote. California is one of the remaining states that does not ask for any identification for in-person voting. Under this measure, anyone voting in person would have to present a government-issued ID to receive a ballot.
A similar requirement would apply to mail-in ballots. Under the measure, a mail-in voter would have to write the last four digits of a unique government-issued identification number (such as Social Security number, driver’s license number, or Voter ID card) on the ballot envelope. That number would be matched against the voter’s registration record before the ballot is counted.
For context, Minnesota already uses a similar system that requires a voter-specific identification number to verify mail-in ballots. To further ensure election integrity, Minnesota law also requires that absentee voters show their blank ballot to a witness (who must be a US citizen, notary, or public official) prior to the voter filling it out, and then requires that witness’s signature on the signature envelope certifying that the ballot was completed privately. Before the ballot is recorded at least two members of the absentee ballot board (either election officials or representatives of different political parties) review each signature envelope to ensure that it matches the voter’s name, address, signature, and voter identification number and has a witness signature.
Proposition 39 includes three more parts to facilitate voter identification and the validation of voter rolls. First, it requires the state to provide a free voter ID card on request, reducing the ballot access issues that can be caused by using a driver’s license as the default identification. Second, it requires the California Secretary of State’s office and county election officials to maintain accurate voter rolls, use government data to verify citizenship attestations, and publicly report each year what share of the rolls has been citizenship-verified. Lastly, it is self-executing, such that every two years the California State Auditor’s Office must publish an audit of state and county election officials’ compliance. It also empowers any citizen to seek judicial review and remedy if they believe that state or county officials are not complying with the constitutional amendment.
2. The legal language
- Full text: Initiative 25-0007A1, “California Voter ID Initiative,” California Office of the Attorney General (as amended August 7, 2025)
- Key language: “Each time a voter casts a ballot in person in any election in the State, the voter shall present government-issued identification, or if voting by mail, the voter shall provide the last four digits of a unique identifying number from government-issued identification that matches the one designated by the voter for their voter registration.”
- What it amends:
Adds Section 3.1 to Article II of the California Constitution, the article that governs voting. Because it is a constitutional amendment, the legislature cannot simply repeal it, and it directs the legislature to enact implementing laws and to provide for military and overseas voters consistent with federal law.
3. Who, What, Where, When, Why?
- What would it change about voting?
It would require a government-issued ID for in-person voting or the provision of the last four digits of a government ID number for mail voting. It requires the state to provide a free state ID card on request. Lastly, it mandates that the state regularly verify the citizenship of registered voters and report the results of that audit. - Where would it take effect?
Statewide, in every election. - When would it take effect?
The measure is self-executing on passage, such that the legislature is directed to enact implementing laws, and the state auditor is directed to publish an audit of compliance by state and county election officials in every odd-numbered year. - Why add identification rules to the voting process?
The proponents’ stated goals for this measure are to promote public confidence in the electoral process and voting results by deterring and detecting fraud, confirming voter eligibility, and minimizing voter impersonation.
4. Trade-offs
The 2020 presidential election results were controversially challenged as being manipulated by widespread voter fraud—an allegation that was believed by three out of every eight voters. The extensive mail-in voting allowed due to COVID-19 pandemic concerns was blamed as part of this alleged fraud. However, documented cases of election fraud are rare, and the most rigorous review of the 2020 election did not find evidence to support claims of systematic fraud.
A more general issue is that voter fraud statistics only measure the fraud that we have been able to detect and, more importantly, the fraud that was perpetrated within the system as it previously existed. The next sections examine:
- The ways that elections have substantially changed over the last fifty years, with major changes accelerating over the last decade
- How these changes provide a rational argument for those concerned with voter fraud
- How the changes, at least in part, seem to be linked to declining voter confidence in elections
The type of fraud inhibited by ID requirements for in-person voting—where one person impersonates another at the polling place—is the rarest documented form of voter fraud. This doesn’t make in-person voter identification unimportant, but in-person voter fraud is arguably the smallest part of the problem. The elephant in the room, so to speak, is the significant increase in mail-in voting.
In brief summary, California’s mail-in voting system verifies eligibility mainly through the voter’s own attestation that they are who they say they are and by matching their signature to a previous signature on record (see the California Decides FAQ: How Elections Are Run for additional information). The lack of a rigorous means to validate who specifically filled out the mail-in ballot—which is done in private, far away from the public view of voting centers—increases the potential for voter fraud. Furthermore, the lack of clearer voter identification mechanisms means that investigations into whether voter fraud occurred will struggle to definitively certify the lack of fraud. That validation gap is precisely the proponents’ argument for building a more complete verification infrastructure.
Changes to US Elections
US elections have seen major changes since states started expanding absentee mail-in voting in the 1970s. This, like early in-person voting, has led to large decreases in voting at public polling locations on Election Day. In the last two presidential elections, over 80 percent of Californians voted by mail.
At the national level:
- In-person voting on Election Day has been steadily decreasing, from around 90 percent of votes cast in the 1990s to 60 percent in 2016. That percentage dropped to 31 percent in 2020 and recovered slightly to 40 percent in 2024.
- Meanwhile, absentee/mail-in voting has been steadily increasing, from around 8 percent of votes cast in the mid-1990s to 21 percent of votes cast in 2016. During the pandemic mail-in ballots surged to 43 percent of votes cast in 2020 and then returned to the previous trend, accounting for 29 percent of votes in 2024.
- Early in-person voting has seen a similar upward trajectory, from 2–3 percent of votes cast in the 1990s to 19 percent in 2016. The trend has accelerated faster than mail-in voting, with early in-person voting accounting for 26 percent of votes cast in 2020 and 31 percent of votes cast in 2024.
The shift away from in-person voting on Election Day seems to have increased voter anxiety about the electoral process, perhaps due to the reduced ability to identify fraud and therefore a perception that fraud would be easier to employ. Currently, eight states now practice all-mail elections (where every eligible voter receives a ballot by mail), twenty-nine more allow no-excuse absentee voting, and forty-seven allow some form of early in-person voting.
California was the first state to allow no-excuse absentee voting, starting in 1979. By 2012, a majority of California ballots were submitted by mail. Starting in 2018, the state allowed county elections officials to shift to an all-mail election, and the state itself adopted an all-mail ballot starting in 2020. This led to over 86 percent of ballots being cast by mail in 2020, followed by over 80 percent in 2024.
Concerns about Ballot Harvesting
In California, concerns about voter fraud have probably been exacerbated by legislation passed in 2016 that legalized unlimited third-party ballot collection, a practice that is more generally known as ballot harvesting. It allows any person to collect and submit any number of mail-in ballots, including paid campaign workers and volunteer advocates. The same year, other legislation enabled county election officials to mail every registered voter a ballot, expand early in-person voting, and create ballot drop box locations with 24/7 access.
In theory, the mail-in ballots should already be filled out and sealed when given to the ballot harvester, such that there’s little opportunity for the harvester to view or change the vote. There is no way to ensure this, but it’s also relevant to highlight that changing another person’s ballot (or filling it out without their approval) has never been legal and is the most fundamental form of voter fraud.
Opponents of ballot harvesting argue that the practice breaks the intrinsic chain of custody for mail-in ballots—from the voter to US Postal Service staff to elections officials—and therefore impugns the integrity of such ballots. Proponents argue that it enables greater voter participation. Both things can be simultaneously true: Many voters likely find it easier to vote, and unscrupulous political agents also have greater ability to practice fraud (regardless of whether they have actually exercised that ability to date or have done so in statistically measurable ways).
By law, the ballot harvester is required to provide their name and signature on the ballot return envelope. However, there currently doesn’t seem to be any way to validate that ballot harvesters are adhering to this requirement, because there’s nothing that distinguishes a ballot submitted by a ballot harvester from one submitted by the voter. The current system effectively places ballot harvesters on the honor system to provide that information on each ballot they submit via mail or ballot drop box, because without providing that information it appears to the elections officials that the voter submitted the ballot themselves.
Decreasing Voter Confidence and Perceived Election Honesty
At the national level, voters’ confidence in whether their own vote is counted correctly is generally high, but there is reduced confidence in whether national voting in general is counted correctly. There is also clearly declining confidence in the general honesty of elections.
It’s important to note that while voter confidence has indeed decreased over recent decades, in the short run a major part of this sentiment seems to be driven by whether a voter’s preferred candidate won the election (called the winner-loser effect). This can be particularly seen in the 2024 election, when Republican-leaning voters went into the election with very low confidence in whether their vote would be counted and then reported greater confidence in US elections following President Trump’s victory. Democratic-leaning voters shifted in the opposite direction, but the size of the change was not as substantial.
5. Conclusion
Passage of Proposition 39 would bring California into line with most other states. Voter ID requirements receive broad, bipartisan support—more than 75 percent of voters support requiring a photo ID to vote—and the ballot measure addresses a real gap in how the state verifies voter eligibility.
The trade-off for greater electoral confidence is that voter ID requirements can cause some eligible ballots to be rejected for honest mistakes. However, the legislature can effectively solve this problem by employing a system similar to that which California already uses, which requires election officials to contact voters to rectify problems with the identification the voter submitted and provides twenty-two days after Election Day to do so.
Learn More About California
Rather than telling voters what to think, California Decides equips them with the facts, historical context, competing perspectives, and policy implications they need to make informed decisions. Through plain-language explainers, short videos, podcasts, webinars, proposition guides, data visualizations, and expert analysis, the initiative transforms complex public policy into accessible, engaging content for a broad audience.
