Federal Election Commission Ellen Weintraub during a committee hearing in the Capitol in 2017. Photo: Joe Raedle/Getty Images

Federal Election Commission commissioner Ellen Weintraub posted an extensive fact-checking thread to Twitter late Wednesday debunking claims by President Trump and some Republicans that mail-in voting can lead to fraud.

Why it matters: Weintraub weighed in after Trump threatened to take action against Twitter for fact-checking him on his earlier unsubstantiated posts claiming mail-in ballots in November's election would be fraudulent, and she directly addressed Twitter's action against the president in her post.

What she's saying: "U.S. citizens will vote by mail this year in record numbers. In the face of a global health emergency, election officials across the country from both parties are working heroically to ensure that voting by mail is accurate, accessible, safe & secure," she tweeted.

  • "There's simply no basis for the conspiracy theory that voting by mail causes fraud. None."

The big picture: Weintraub's comments come as White House press secretary Kayleigh McEnany told news outlets including Axios that President Trump planned to sign an executive order aimed at social media companies on Thursday.

  • Trump accused Twitter of interfering in November's elections by fact-checking him.
  • Twitter CEO Jack Dorsey clarified on the microblogging site Wednesday night that the firm fact-checked Trump's tweets amid concern they "may mislead people into thinking they don't need to register to get a ballot (only registered voters receive ballots)."
  • Trump and some Republicans have repeatedly railed against states that have announced plans to expand voting-by-mail options during the coronavirus pandemic, casting doubt on the reliability of the system.

Of note: Weintraub recommended in March that Americans should vote in the general election by mail if physically going to the polls remained unsafe because of the threat of the novel coronavirus.

  • Last year, Weintraub told CNN there was "no evidence of rampant voter fraud in 2016 or really in any previous election," despite Trump's claims.
  • Weintraub said at the time such statements from the president can cause "people to lose faith" and "to question the results." She also sent him a letter asking him "to provide any evidence" that could prove his claims.

Go deeper: Podcast: Trump vs. Twitter ... vs. Trump

Editor's note: This article has been updated with new details throughout.

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