Will the Supreme Court rule by July 3, 2027 that Arizona can require documentary proof of citizenship from voters who register with the state form?

We put the chance at 72% that the Supreme Court rules by July 3, 2027 that Arizona may require documentary proof of citizenship from voters using its state registration form. The biggest reason: five justices already let Arizona enforce that exact requirement in an August 2024 emergency order, and the Court took the case to review a ruling against it.

Evidence cutoff Version 1 of 1By the TPG Forecast Desk, edited by Frank Carrasco, PhD#1a9dbfb0da

Why it matters: The ruling decides whether states can make new voters show a birth certificate, passport or similar document when they register, a rule several Republican-led states want to copy before the 2028 presidential election.

TPG forecast

72%

Likely

The justices already let it run

Our odds over timeTPG forecastMarket
0%25%50%75%100%Resolves Jul 3, 2027Sep 26, 2026

Version 1: 72% (range 60% to 82%) · Kalshi 69%

Evidence cutoff Sep 26, 2026 · published Sep 26, 2026 · Likely, the justices already let it run

This forecast is on its first version. Each update adds a point; old versions are never edited.

The numbers behind the call

5-4

vote in August 2024 letting Arizona enforce state-form proof of citizenship[1]

7-2

2013 ruling that barred the requirement for the federal form only[2]

19,000

Arizonans registered as federal-only voters as of July 2023[3]

9%

of voting-age citizens lack ready proof of citizenship, per a Brennan Center study[4]

1,600

alleged noncitizens Virginia was allowed to remove inside the 90-day window in 2024[5]

Dec 8, 2026

oral argument date[6]

What it means for you

Arizona voters

More than 19,000 Arizonans were registered as federal-only voters as of July 2023 because they had not shown documents. A YES ruling would push new state-form registrants to produce proof or be limited to federal races.

Citizens without documents on hand

The Brennan Center estimates more than 9% of voting-age citizens do not have proof of citizenship readily available. Students, older voters, married women whose names changed and rural residents would need to track down records before registering.

Other states

A YES ruling would give Republican-led legislatures a tested template for documentary proof laws on their own state forms, while Democratic-led states would be unaffected unless they choose to act.

County election offices

Offices would need systems to collect and verify documents and to run two classes of registrants, adding cost and staff time ahead of the 2028 cycle.

Voter registration groups

Drives that register people on the spot would become harder, since applicants may not carry a birth certificate or passport, pushing groups toward the federal form, which Arizona must still accept.

The read

Three lenses, always in this order. How the method works.

01

Psychology

What do the decision makers need?

The key votes are Chief Justice Roberts and Justice Kavanaugh. In August 2024 they joined Justices Thomas, Alito and Gorsuch to let Arizona enforce the state-form proof requirement while the case continued, even though they declined to let the rest of the law take effect before the election. Voting to let a rule operate and then striking it down on the merits is possible, but justices rarely reverse their own interim judgment without a new argument that changes the picture.

Justice Barrett is the uncertain vote. In 2024 she sided with the three liberal justices to deny the application entirely. That vote may have been driven by the timing concern of changing election rules months before an election, which does not apply to a merits ruling in 2027. Her record on federal preemption favors reading federal statutes by their text, and the National Voter Registration Act's accept and use command speaks to the federal form, not a state's own form.

Chief Justice Roberts has institutional reasons to decide this well before the 2028 cycle and to write narrowly. The most natural narrow ruling for him is that Congress regulated the federal form and left the state form alone, which is a YES on our question even if the Court sides with the challengers on the 90-day removal issue.

02

History

What happened the last times this came up?

The closest analogue is Arizona v. Inter Tribal Council in 2013, where the Court ruled 7-2 that the NVRA preempts Arizona's proof requirement for people using the federal form. Justice Scalia wrote that opinion and Roberts joined it. It cuts both ways: it shows the Court reads the NVRA seriously, but its reasoning rested on the federal form specifically, which leaves the state form open. That is why Arizona built its two-track system in the first place.

The second analogue is Beals v. Virginia Coalition for Immigrant Rights in October 2024, where the Court allowed Virginia to keep removing roughly 1,600 alleged noncitizens from its rolls inside the NVRA's 90-day quiet period, over the dissent of the three liberal justices. Together with the August 2024 Arizona order, the Court has granted emergency relief to the state on both questions now before it, as the RNC's petition emphasizes.

Where the analogies break: emergency orders are not merits rulings, and the consent decree issue is new. A 2018 agreement by a prior Arizona Secretary of State to accept state forms without documents is a separate barrier, and the Court could find the NVRA allows the requirement but the decree still binds. Most of the conservative majority has been skeptical of consent decrees that bind future officials, which limits that risk.

03

Statistics

Base rate, adjustments, the number.

Start with the Court's overall reversal rate, about 70% for the cases it chooses to hear, and higher for the Ninth Circuit. That gives a prior of about 0.72 for the RNC on at least one question.

Adjust up for the August 2024 interim order, where five justices sided with Arizona on exactly this state-form question: plus 8 points. Adjust down for the consent decree as an independent ground to rule against Arizona: minus 4 points. Adjust down for a dismissal, a standing problem, or a split decision where the Court rules against Arizona on proof but for it on removals: minus 4 points. 0.72 plus 0.08 minus 0.08 equals 0.72.

The Kalshi market requires Arizona to win on both questions and last traded at 69 cents on very thin volume. Our question needs only the proof-of-citizenship win, so our number should sit at or slightly above that market, and it does.

Between the lines

What people spent versus what they said, and what was left out.

Costly signal

In August 2024, Roberts and Kavanaugh split the difference: they let Arizona enforce proof of citizenship for the state form but not the rest of the law.

That was a deliberate, reasoned line, not a coin flip. It maps exactly onto question one here, and it suggests the Court's center already sees the state form as the state's own business.

Sequencing

The Court granted this case on June 29, 2026 and set argument for December 8, 2026, after the midterms.

The timing lets the justices avoid changing rules close to an election, which was Barrett's likely concern in 2024, while still deciding the issue well before 2028. Removing the election-timing objection helps the state.

Personnel move

The petitioners are the Republican National Committee and Republican legislative leaders rather than Arizona's Democratic executive officials, with the Justice Department filing in support.

Standing is the hidden risk. If the Court doubts that a party committee or legislators can defend a state law in place of the state's own executive officers, it could dismiss without reaching the merits. We carry that as a few points of NO.

What was left out

The Court took the RNC's two questions as written, including the consent decree, rather than limiting the grant to the NVRA.

Including the decree question means the justices intend to decide whether a past official's settlement can bind a state indefinitely, a question on which the conservative majority has signaled skepticism. That reduces the chance the decree becomes the reason for a NO.

Base rate

70%

approximate share of cases the Supreme Court reverses or vacates after granting review[1]

Long-run average of the Court's reversal rate across recent terms, used as the neutral prior for the petitioning party. Adjusted in the statistics lens using the 2024 emergency order in this same case.

Closest historical parallels

  • Arizona v. Inter Tribal Council of Arizona (2013)

    Alike: Same Arizona proof-of-citizenship requirement, same federal statute.

    Outcome: 7-2 against Arizona for federal-form applicants.

    Where it breaks: The holding rested on the federal form's accept and use mandate. This case is about the state's own form.

  • RNC v. Mi Familia Vota emergency order (2024)

    Alike: Same case, same state-form question.

    Outcome: 5-4 to let Arizona enforce state-form proof of citizenship for the 2024 cycle.

    Where it breaks: An interim order with no reasoning, shaped by the election calendar. Merits review is fuller and Barrett's vote is not fixed.

  • Beals v. Virginia Coalition for Immigrant Rights (2024)

    Alike: Emergency ruling on the NVRA's 90-day quiet period for removing alleged noncitizens.

    Outcome: Virginia allowed to continue removals of roughly 1,600 registrants.

    Where it breaks: Concerns the second question, which does not decide this forecast, and was also an unexplained interim order.

How it could play out

Every path we see, sized by probability. Paths that resolve YES add up to our 72%.

  • Arizona wins both questions Yes50%

    Majority reads the NVRA as regulating only the federal form and the quiet period as not covering noncitizen removals, and rejects the consent decree as a bar.

  • Arizona wins on proof, loses on 90-day removals Yes22%

    Roberts or Barrett joins a narrow holding on the state form but reads the quiet period provision to cover systematic removals.

  • Arizona loses on proof of citizenship No22%

    Majority holds the NVRA or the 2018 consent decree bars the state-form requirement.

  • Dismissed, vacated on standing, or not decided by July 3, 2027 No6%

    Court doubts the RNC or legislators can defend the law, or the case is reargued.

What would change our number

↑

At the December 8 argument, Barrett questions whether the NVRA says anything about state forms

+6 points
↓

Justices spend significant time on whether the RNC and legislative leaders have standing

-8 points
↓

Roberts presses the RNC on why the 2018 consent decree does not bind the state

-6 points
↓

Congress passes a federal proof-of-citizenship law such as the SAVE Act before the decision

Adds mootness risk, -3 points

TPG 72% vs Kalshi 69%

The Kalshi contract requires Arizona to win on both proof of citizenship and the 90-day removal question before August 2028, and it has traded fewer than 100 contracts. Our question needs only the first win, so we sit slightly higher at 72%. The thin volume means the market price carries little information.

Market price recorded September 26, 2026 from Kalshi. Analysis, not investment advice.

How this question resolves

Resolves YES if, on or before July 3, 2027, a majority of the Supreme Court in Republican National Committee v. Mi Familia Vota (No. 25-1017) holds that neither the National Voter Registration Act nor the 2018 federal consent decree bars Arizona from requiring voter-registration applicants who use the state registration form to produce satisfactory evidence of U.S. citizenship. The outcome on the second question (removing noncitizens within 90 days of a federal election) does not affect resolution. Resolves NO if the Court holds that federal law or the consent decree bars the requirement, dismisses the case, vacates on standing or other procedural grounds without reaching the question, or issues no decision by July 3, 2027.

Closes: July 3, 2027. Judged by: The Supreme Court's published opinion in No. 25-1017 on supremecourt.gov, as summarized by SCOTUSblog

Questions people ask

Will the Supreme Court allow proof of citizenship to register to vote?

+

The TPG Forecast Desk puts the chance at 72% that the Supreme Court rules by July 3, 2027 that Arizona can require documentary proof of citizenship from people who register using the state form. Five justices already let Arizona enforce that rule in August 2024. The federal form, which Arizona must accept, is not affected.

What is RNC v. Mi Familia Vota?

+

Republican National Committee v. Mi Familia Vota is a Supreme Court case on two Arizona laws from 2022. It asks whether federal law or a 2018 consent decree stops Arizona from requiring proof of citizenship on its state voter form, and whether Arizona can remove suspected noncitizens within 90 days of a federal election. Argument is December 8, 2026.

What is a federal-only voter in Arizona?

+

A federal-only voter in Arizona is someone who registered without showing documentary proof of citizenship. Because the Supreme Court ruled in 2013 that Arizona must accept the federal form, these voters can vote in federal races but not state and local ones. More than 19,000 Arizonans were in that category as of July 2023.

Does the Mi Familia Vota case affect the 2026 midterms?

+

No. The Supreme Court scheduled argument for December 8, 2026, after the November 3 midterm election, and a decision is expected by the end of June 2027. The ruling will shape registration rules for the 2028 presidential election in Arizona and in any state that copies its law.

Sources

Every source is dated on or before the September 26, 2026 evidence cutoff. Nothing published later was used.

  1. [1]Justices allow Arizona to enforce proof-of-citizenship law for 2024 voter registration. SCOTUSblog, Aug 22, 2024.

    “The vote was 5-4”

  2. [2]Arizona v. Inter Tribal Council of Arizona. American Civil Liberties Union, Jun 17, 2013.

    “On June 17, 2013, in a 7-2 ruling, the Supreme Court invalidated Arizona's burdensome voter registration requirement”

  3. [3]Supreme Court takes up GOP bid to revive Arizona proof of citizenship law that critics call voter suppression. Cronkite News, Jun 29, 2026.

    “More than 19,000 Arizonans were registered as federal-only voters as of July 2023, according to court records”

  4. [4]Supreme Court takes up GOP bid to revive Arizona proof of citizenship law that critics call voter suppression. Cronkite News, Jun 29, 2026.

    “found that more than 9% of U.S. citizens of voting age do not have proof of citizenship readily available”

  5. [5]Supreme Court clears way for Virginia to remove 1,600 alleged noncitizens from voter rolls. CBS News, Oct 30, 2024.

    “allowed Virginia to move forward with its removal of roughly 1,600 alleged noncitizens from its voter rolls”

  6. [6]Republican National Committee v. Mi Familia Vota (25-1017) case page. SCOTUSblog, Sep 4, 2026.

    “Argument Dec 8, 2026”

Version history and integrity

Published forecasts are never edited. When the evidence changes we publish a new version beside the old one, each locked with a sha256 hash of its full contents. When this question resolves it is scored in public on our track record.

VersionCutoffForecastLock hash
v1Sep 26, 202672% Likely1a9dbfb0da00de1341d8429e88723aa71b840fa8196b91b0e82c03d7d3c16f2f

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