VOTE YES ON PROP 40
Vote Yes on Prop 40. Let the actual proposal and the legal record—not predictions stated as certainties—guide the decision.
The facts at a glance
The drafters have published their responses to legal objections. [1]
The statute contains severability and alternative-apportionment provisions. [2]
A legal analysis is not a judicial ruling.
A prediction is not an outcome
The fact that some lawyers have asserted potential challenges is a far cry from saying any of those challenges will prevail, they won’t.
This page does not assert that litigation won’t happen, it may. After all, the billionaires have lots of money and lawyers. It explains why the legal materials cited here do not justify saying the measure won’t work.
The state-law question is not the same as a federal wealth-tax question
Galle, Gamage, and Shanske explain that constitutional arguments aimed at a federal tax do not automatically decide whether a state may impose one. Their analysis also distinguishes taxation from a taking of property. These are attributed arguments by the measure’s drafters, not guarantees of how a court will rule. [1]
Prop 40 is expressly a California constitutional amendment and statute. Its legal analysis needs to start with that proposal—not with a different federal tax that voters are not being asked to approve. [2]
The January date is written into the proposal
The tax-obligation date precedes the November vote. The drafters’ paper addresses objections to that feature. The statute also directs courts, within constitutional limits, to use limited adjustments where possible if a date or application cannot lawfully be enforced. [1][2]
That provision does not give the campaign power to decide constitutional questions. It does show that the proposal anticipates disputes over particular applications and does not treat every possible defect as a reason to discard the entire structure. [2]
A dispute over part is not automatically a defeat of the whole
Section 50311 contains severability rules: an invalid provision or application is not intended to invalidate other enforceable parts. Section 50306 provides an alternative-apportionment process for claims that the standard treatment does not fairly reflect the relevant California connection. [2]
The proposed constitutional text also allows a specified validation challenge without requiring payment of the contested tax first, and preserves other review rights within its terms. These mechanisms are part of the legal design—not proof that anyone is forbidden to challenge it. [2]
Separate the other ballot measures from this legal debate
The official LAO analysis warns that higher Yes-vote totals for Proposition 41 or 42 could create conflicts preventing Prop 40 from taking effect. That is a specific interaction worth recognizing. It is different from a lawyer arguing that all state wealth taxes are unconstitutional. [3]
Precision is useful to voters: a possible conflict, a claim about one taxpayer, and a final judgment against the entire measure are different things. A responsible explanation should say which one it actually has evidence for.
The reason to vote Yes remains protecting care
The proposal directs the large majority of net receipts to healthcare and permits spending to protect coverage and prevent service losses. That public purpose should not disappear behind a prediction presented as a verdict. [2]
Vote on the measure and the evidence supporting it. A threatened lawsuit does not decide the question for California; voters have a choice about how to protect care.
The people and institutions behind the evidence
Measure drafter and legal-analysis author
Brian Galle
The July 2026 explanatory report identifies Brian Galle with UC Berkeley. A measure drafter and coauthor of the legal analysis, he also explains the proposal in a Berkeley Law interview. [1] [4] [5]
Measure drafter and legal-analysis author
David Gamage
The July 2026 explanatory report identifies David Gamage with the University of Missouri. He is a measure drafter and coauthor of the legal and valuation analyses. [1] [4] [6]
Measure drafter and legal-analysis author
Darien Shanske
The July 2026 explanatory report identifies Darien Shanske with UC Davis. He is a measure drafter and coauthor of the legal and valuation analyses. [1] [4] [6]
Hear more from the people involved
INTERVIEW + READABLE TRANSCRIPT
Professor Brian Galle on “How to Tax the Ultrarich”
A Berkeley Law interview with a full transcript about taxing the ultrarich. Galle distinguishes federal reform from the California proposal he helped draft.
Open the original source →Keep reading
THE PAIRED PAGE
How Prop 40 Gives California a Way to Tax Billionaire Wealth
Read the detailed page →
WHY VOTE YES
Where the Money Goes: Healthcare, Education and Food
Read the detailed page →
CHECK THE EVIDENCE
Sources behind this page
Each reference identifies what it establishes. A cited agency or researcher is not automatically a campaign endorser.
01Correcting the Record: Addressing Some Legal Arguments About the 2026 Billionaire Tax Act
Brian Galle, David Gamage, and Darien Shanske · Revised January 9, 2026 · Proponent legal analysis
Galle, Gamage, and Shanske explain their defense of the proposal using existing court decisions. This is the drafters’ legal analysis, not a ruling on Prop 40.
Where to look:
https://eml.berkeley.edu/~saez/galle-gamage-shanskeCBTAlegal.pdf
02Proposition 40: text of proposed laws
California Secretary of State · 2026 voter guide · Proposed law
The actual proposed rules on taxpayer eligibility, valuation, payments, spending, and reporting. Tax payments begin in 2027; audit authority and special trust rules remain. Section 50310 governs possible amendments.
Where to look: Gov. Code §16355, PDF pp. 4–5; Rev. & Tax. Code §§50301, 50303–50304, 50308–50312, PDF pp. 5–13.
https://vig.cdn.sos.ca.gov/2026/general/pdf/prop40-text-proposed-laws.pdf
03Proposition 40: official analysis
California Legislative Analyst’s Office · 2026 voter guide · Official fiscal analysis
Estimates tens of billions in new wealth-tax revenue over several years and possible income-tax losses of less than $1 billion a year. These periods differ: the figures are not a calculation of the lifetime net balance. The analysis also covers administration and interaction with Propositions 41 and 42.
Where to look: Fiscal Effects; Other Measures That May Prevent Proposition 40 From Taking Effect
https://voterguide.sos.ca.gov/propositions/40/analysis.htm
04The California Billionaire Tax: an expert report
Brian Galle, David Gamage, Emmanuel Saez, and Darien Shanske · Updated July 20, 2026 · Proponent expert report
The proposal’s drafters explain its funding estimates, payment installments, and qualifying deferral arrangements.
Where to look:
https://eml.berkeley.edu/~saez/galle-gamage-saez-shanskeCAbillionairetaxJuly26.pdf
05Professor Brian Galle on “How to Tax the Ultrarich”
Berkeley Law Voices Carry; host Gwyneth Shaw · February 17, 2026 · Interview with full transcript
A Berkeley Law interview with a full transcript about taxing the ultrarich. Galle distinguishes federal reform from the California proposal he helped draft.
Where to look:
https://www.law.berkeley.edu/podcast-episode/professor-brian-galle-how-to-tax-the-ultrarich-voices-carry/
06Expert Report on Valuation of Controlling Shares of Publicly Traded Companies Under the CBTA
Brian Galle, David Gamage, Emmanuel Saez, and Darien Shanske · February 5, 2026 · Proponent technical analysis
Explains publicly traded shares, private-company valuation rules, and certified appraisals.
Where to look:
https://eml.berkeley.edu/~saez/galle-gamage-saez-shanskeCBTAcontrollingshares.pdf
About this page. Published as a review draft by the Yes on 40 campaign, which advocates passage of the measure. Sources were checked on September 10, 2026. Research estimates, proposed legal provisions and endorsements are identified separately. This page is not individual tax or legal advice. Send corrections with the relevant source to the campaign’s press contact.
Vote Yes on Prop 40.
Vote Yes on Prop 40. A prediction about litigation is not a substitute for California’s decision about protecting healthcare.