A conservative dark-money group based in Ohio has dropped $2.2 million on a Colorado measure that, if passed by voters, would significantly tighten requirements for mail ballots. The Coalition for American Prosperity and Growth is the only donor to the Colorado Voter Trust Initiative, a state-level spending political action committee that is backing Amendment 84 in the Nov. 3 election. The ...

A voter drops off his ballot for the 2022 Colorado primaries at a ballot drop-off box at Union Station on June 28, 2022, in Denver.

Jintak Han/The Denver Post/TNS

A conservative dark-money group based in Ohio has dropped $2.2 million on a Colorado measure that, if passed by voters, would significantly tighten requirements for mail ballots.

The Coalition for American Prosperity and Growth is the only donor to the Colorado Voter Trust Initiative, a state-level spending political action committee that is backing Amendment 84 in the Nov. 3 election.

The ballot measure would require Coloradans returning their mail ballots to write, in the same place they sign on the envelope containing their ballot, either the last four digits of their Social Security number, their driver’s license number or an ID card number. If they didn’t, the ballot would be set aside until the voter provided the identification info.

All of the coalition’s donations were made between June 1 and July 1, state campaign finance records show.

But it’s unclear who is spending so significantly to back the proposal. The group — whose donations are considered dark money because it does not disclose its donors — is not registered as a business or nonprofit with the Colorado Secretary of State’s Office. The address listed on its donations leads to a mail service in Colorado Springs, a common tactic for groups seeking to hide their benefactors.

Suzanne Taheri, the conservative attorney who serves as the registered agent for the PAC that received the donations, did not respond to an email seeking comment.

The group also does not appear to be based in Colorado. A group of the same name is registered in Ohio, and it was the chief financier for a federal spending PAC that opposed the candidacy of Daniel Cameron, the former Kentucky attorney general who lost a contested Republican primary earlier this year to succeed U.S. Sen. Mitch McConnell in the Senate. The group donated $3.85 million to that PAC.

The only other information listed on those donations is a Florida ZIP code for West Palm Beach.

The group was previously known as the Coalition for Ohio Prosperity and Growth. Under that name, it donated $2.1 million to conservative causes in 2024, according to federal tax records, and it spent $100,000 on a political consultant who previously led the Ohio GOP and worked on two of President Donald Trump’s campaigns. The group’s address on its tax returns is for a postal store in Arlington, Virginia.

Nearly all of the coalition’s 2024 cash went to Conservative Agenda for America, which in turn donated to other conservative causes and, earlier this year, backed U.S. Rep. Andy Barr. He beat Cameron for the Senate nomination in Kentucky.

Conservative Agenda for America also recently changed its name. In 2023, it was first registered in Ohio as “Protect Women Ohio,” another dark-money operation that spent millions of dollars against an abortion-rights ballot measure. It changed its name in 2024, and its tax filing lists a UPS store address in Arlington.

Colorado’s Amendment 84 is similar to California’s Proposition 39 in the fall election, which would also require voters to provide identifying information on mailed ballots. The primary backer of the California campaign is billionaire Richard Uihlein, who has spent $17 million on the effort, according to the San Francisco Chronicle. Uihlein also spent heavily trying to scuttle the Ohio abortion measure in 2023.

It’s unclear who’s funding the Coalition for American Prosperity and Growth or why an apparently Ohio-based group is spending a seven-figure sum to change how Coloradans vote. An email sent to the Ohio attorney who changed the organization’s name was not returned. A message left for a number listed on the group’s 2024 tax return was also not returned.

The group opposing Amendment 84, Defend Our Ballots, also did not return a message seeking comment for this story.

(Staff writer Nick Coltrain contributed to this story.)