Sen. Cory Gardner, R-Colo., speaks on Capitol Hill in Washington, in July 2015.

(AP Photo/Manuel Balce Ceneta)

Republican U.S. Sen. Cory Gardner says that if Donald Trump doesn’t step down as the party’s presidential nominee, he’ll write in his vote for Trump's vice presidential nominee Mike Pence instead. But Suzanne Staiert, Colorado’s deputy secretary of state, says that to be considered as a write-in candidate in Colorado, the person has to file an affidavit 15 days before the election for votes to count toward them.

"If you write in somebody who hasn’t accepted essentially a nomination or petitioned to do that, the vote doesn’t count for the write-in. It’s not tabulated," she told Colorado Matters host Ryan Warner.

Gardner, Rep. Mike Coffman and Senate candidate Darryl Glenn all called on Trump to leave the ticket this weekend after he was caught on tape in 2005 describing what amounts to sexually assaulting women. Most of the rest of Colorado's Republicans in Congress have said they're disappointed with the tape, but that they stand by the candidate. Trump has said repeatedly has no plans to step aside. More conversation highlights:

It’s too late to reprint ballots:

“Most of Colorado's ballots have been printed. We’ve had ballots out to our military and overseas voters for a couple of weeks now and the bulk of the rest of the ballots have been printed and are ready to mail next Monday.”

What happens if a candidate withdraws after ballots are printed?

“Those votes are counted for whoever fills the vacancy.”

And if someone says they’re going to write-in Mike Pence?

“They won't be counted. It'll just count as an undervote essentially unless the Republican Party makes some sort of change.”

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Editor's note: Deputy Secretary of State Suzanne Staiert misspoke when she said a write-in candidate would need to file an affidavit 15 days before the election for votes to count. In fact, the affidavit would have to have been filed at least 110 days before the election.