Colorado ballot measure · November 3, 2026

Colorado Amendment 84, explained

ID number required on mail ballots. 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

Shall there be an amendment to the Colorado Constitution requiring a voter to sign and include the last four digits of their social security number or their Colorado driver's license or identification card number on the outside of their mail ballot for any federal or state election, and, in connection therewith, allowing the voter to correct missing or incorrect information, including with alternative forms of identification; and prohibiting a county clerk and recorder from counting the mail ballot unless the problem is fixed?

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

What it actually means

Colorado verifies mail ballots by matching the signature on the envelope. This amendment adds a second check for federal and state elections: voters would also write the last four digits of their Social Security number or their Colorado driver's license or ID number. Ballots with a missing or mismatched number would not count unless the voter fixes it within eight days after the election.

If you vote YES

Mail voters in federal and state elections would have to sign and include the last four digits of a Social Security number, Colorado driver's license number or Colorado ID card number (Real ID-compliant), in addition to signature verification.
If the number is missing or does not match, the county must contact the voter, who has eight days after election day to fix it with an accepted ID, a U.S. passport, a U.S. military ID or a tribal photo ID; otherwise the ballot is not counted.
In-person ID rules would not change.
State and county costs would be up to $2.7 million in 2026-27 and $1.2 million a year after, and business filing fees at the Secretary of State's office may rise to cover the state's share.

If you vote NO

Mail ballots would continue to be verified only by comparing the envelope signature with signatures on file; a mismatch is reviewed by two judges of different parties before the voter is contacted.
Voters with a signature discrepancy would still have eight days after the election to confirm their identity.
92% of ballots cast in 2024 were mail ballots, and that system would continue unchanged.

The numbers that matter

State and local cost: Up to $2.7 million in 2026-27; up to $1.2 million a year after
Share of 2024 ballots cast by mail: 92%
Vote needed: 55%

Why supporters say YES

An ID number is more consistent and less subjective than signature matching, strengthening election security and public confidence while keeping mail voting convenient; voters without the listed IDs can still vote in person.
— Colorado Blue Book argument for Amendment 84 (Legislative Council Staff)

Why opponents say NO

The measure adds a burden without meaningfully improving security; minor mistakes could cause eligible ballots to be rejected, and privacy concerns could discourage mail voting, while the current signature system already catches rare cases of fraud.
— Colorado Blue Book argument against Amendment 84 (Legislative Council Staff)

What’s genuinely uncertain

How many ballots would be set aside for missing or mismatched numbers, and how many would be cured, is not estimated.
The measure is backed by the Coalition for American Prosperity and Growth, according to Colorado Newsline; no registered opposition committee was identified in the sources reviewed.

The bottom line

A second, number-based check on mail ballots, against more chances for eligible ballots to be set aside and added cost for counties.

One neutral sentence describing the tradeoff — not a recommendation.

Sources:leg.colorado.gov coloradosos.gov coloradonewsline.com

Checking it against the official text

The Colorado 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 Colorado Secretary of State.

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