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.

Go deeper

Russia likely to keep amplifying criticism of mail-in voting, DHS says

Acting DHS Secretary Chad Wolf testifies to the Senate Homeland Security and Governmental Affairs Committee on August 6. Photo: Alex Wong/Pool/AFP via Getty Images

The Department of Homeland Security's intelligence branch warned law enforcement Thursday that it believes Russian-controlled social media trolls and state media are likely to continue trying to sow distrust in U.S. election results and mail-in ballots, ABC News first reported.

Why it matters: Americans are expected to vote by mail in record numbers in November's election due to the coronavirus pandemic, which means it may be days or weeks after election day before it's clear who won the presidency and down-ballot races.

Updated Sep 4, 2020 - Technology

Zuckerberg warns of post-election violence

Mark Zuckerberg tells "Axios on HBO" that Facebook is imposing new election rules to deter use of the platform to spread of misinformation and even violence, and to help voters see the results as "legitimate and fair."

Driving the news: The new measures, announced Thursday, include throwing a flag on posts by candidates who claim premature victory, and forbidding new ads within a week of Election Day.

Sep 3, 2020 - Technology

Facebook says it will remove videos of Trump saying to vote twice

Photo: Mandel Ngan/AFP via Getty Images

Facebook, citing its policies against voter fraud, will take down a video of President Trump suggesting people vote twice in North Carolina if it's being shared approvingly, the company said Thursday.

Yes, but: It hasn't taken down any instances of the video yet. Facebook said people are fine to post it if they include context around Trump's comments.