Maine Republican Sen. Susan Collins rejected Atlantic writer David Frum’s claim that Collins asked Majority Leader Mitch McConnell for permission to vote in favor of new witnesses in the impeachment trial last week.

“I dont know why I feel so sure of this, yet I am sure: Susan Collins asked Mitch McConnell for permission to vote for witnesses. Mitt Romney didn’t,” Frum wrote on Twitter Friday.

I dont know why I feel so sure of this, yet I am sure: Susan Collins asked Mitch McConnell for permission to vote for witnesses. Mitt Romney didn't. — David Frum (@davidfrum) February 1, 2020

Collins characterized the comment as “sexist,” on Fox News during an interview with Martha MacCallum.

“You know Martha, I have cast more than 7,000 votes in my Senate time and I’ve never asked anyone for permission on how to vote,” Collins explained. “So that is just totally wrong, and I would also argue that it’s very sexist.”

MacCallum asked Collins about the threats she has received since announcing she would vote to acquit the president in Wednesday’s impeachment vote and played several of the threatening constituent voicemails on air.

“Wow, what a vile piece of garbage you are, Susan Collins… I sure hope you didn’t breed. I sure hope you don’t have children or grandchildren, because their failure is [expletive],” one caller said.

“You are a traitor that you support people like Vladimir Putin and Donald Trump.”

“You’re going to lose, Susan Collins. You’re going to lose. You’re just a little [expletive] for Donald Trump,” said another.

Collins said it was simply a “continuation of the kind of abuse and harassment that has occurred for my staff, my family, and me since my vote for Justice Kavanaugh.”

“I think it’s a sad commentary that we can’t have differences of opinion without resorting to profanity, to death threats, to vile language,” Collins added.

The Maine Republican was one of the few swing votes on impeachment as the senator was only one of two Republicans in the Senate Friday to vote for new witnesses to testify in the impeachment trial. The other senator was Sen. Mitt Romney of Utah.

While Romney ultimately voted to remove Trump from office without hearing from additional witnesses, Collins voted for acquittal.