California ballot measure · November 3, 2026

California Proposition 39, explained

Voter identification and citizenship verification. A ballot measure is a yes-or-no question put directly to voters — no candidate is involved, and the wording on the ballot is the wording that becomes law. This page shows that wording first, then what it actually changes.

The official wording

PROHIBITS CITIZENS FROM VOTING UNLESS THEY PRESENT GOVERNMENT-ISSUED IDENTIFICATION. INITIATIVE CONSTITUTIONAL AMENDMENT. Invalidates mail ballots that do not have last four digits of designated government-issued identification number written on envelope. Prohibits in-person voting without presenting government-issued identification. Fiscal Impact: Costs of between tens of millions of dollars and low hundreds of millions of dollars each year to implement new voting requirements.

This is what appears on the ballot. Everything below explains it.

What it actually means

Amends the state constitution to require voters to show government-issued identification when voting in person, and to write the last four digits of a designated ID number on their mail ballot envelope. It also requires election officials to try to verify registered voters' citizenship using government data and to report the results. The Legislature would have to pass laws to fill in details.

If you vote YES

In-person voters would have to present government-issued identification.
To vote by mail, new and existing voters would have to designate a government-issued ID number in their registration, and write its last four digits on each ballot envelope; a ballot with a missing or non-matching number would not count.
The state would provide a free voter ID card to anyone who asks.
Election officials would have to make "best efforts" to verify voters' citizenship with government data and report each county's verification rate every year; the State Auditor would review compliance every odd-numbered year.
State and local costs would be tens of millions to low hundreds of millions of dollars a year.

If you vote NO

Voters' identity would continue to be established at registration (with a driver's license, state ID or last four digits of a Social Security number) and by signature when voting.
Mail ballots would continue to be counted after election officials verify the signature on the envelope; in-person voters would continue to sign the roster without showing ID, except some first-time voters.
There would be no new citizenship-verification reporting requirement.

The numbers that matter

Annual state and local cost: Tens of millions to low hundreds of millions of dollars
Mail ballots cast, November 2024: About 13 million of 16 million

Why supporters say YES

Voter ID is supported across parties and would increase trust in elections; the measure keeps mail voting and guarantees a free ID, and would replace a signature-matching process under which more than 100,000 ballots were rejected in the last election.
— Official argument in favor, signed by the Democratic, Republican and Independent coalition chairs of Californians for Voter ID
Accurate voter lists, citizenship checks and independent audits every two years would strengthen election management, and states with voter ID laws have not seen lower participation.
— Official rebuttal, signed by The Transparency Foundation, the California Women's Leadership Association and the Latino American Political Association

Why opponents say NO

An ID number on the envelope that must exactly match state records creates new ways to reject eligible ballots, and printing part of an ID number on the outside of an envelope exposes voters to identity theft.
— Official argument against, signed by ACLU California Action, Common Cause and the League of Women Voters of California
Election officials already verify voters; the measure adds costs of up to hundreds of millions of dollars a year and extra hurdles that fall hardest on seniors, students, low-income workers and people who have changed their names.
— Official rebuttal to the argument in favor, signed by U.S. Senator Alex Padilla, the California Nurses Association and the California School Employees Association

What’s genuinely uncertain

Many details are left to the Legislature, including which forms of ID count and what "best efforts" to verify citizenship means, so the practical effect depends on laws not yet written.
The ballot title was rewritten by the Attorney General after the measure qualified. Proponents (Californians for Voter ID v. Weber) sued over it; a Sacramento Superior Court judge ruled on August 6, 2026 that the new title was sufficient.
In Rivas v. Weber, filed by the Assembly Speaker and Senate President pro Tem, a Sacramento Superior Court judge found claims in the proponents' submitted ballot arguments false and misleading. The arguments summarised above are as printed in the final guide.
Cost estimates range widely because they depend on how the ID card and verification systems are designed and how many cards are requested.

The bottom line

A uniform ID check on every ballot that supporters say builds trust, against new requirements that could cause some eligible voters' ballots to be rejected and cost up to hundreds of millions a year.

One neutral sentence describing the tradeoff — not a recommendation.

Sources:vig.cdn.sos.ca.gov ballotpedia.org

Checking it against the official text

The California Secretary of State publishes the certified measures and, in most states, an official voter guide with fiscal notes. That is the authoritative version. Everything here is an explanation of it, not a substitute for it.

Confirm this with the official source

Your ballot is determined by your election authority, not by us. Verify your registration, precinct, and sample ballot at California Secretary of State.

Other measures on the California ballot

Candidates on the same ballot

Everything on the California ballot →