Donald Trump used Twitter to make outrageous claims throughout his 2016 presidential campaign, and he’s still making them after winning the presidency. If he keeps it up as president, he will turn Twitter into a state-media machine capable of quickly and widely spreading disinformation.

In the middle of a rant today about the Electoral College, Trump tweeted a preposterous claim: that millions of people voted illegally in the election he just won. (Trump also trashed democratic norms before the election, saying it would be rigged and that he would not accept the results if he lost.) Trump made the false claim about illegal voting today in the middle of saying there should be no vote recount in Wisconsin.

In addition to winning the Electoral College in a landslide, I won the popular vote if you deduct the millions of people who voted illegally — Donald J. Trump (@realDonaldTrump) November 27, 2016

There is no evidence that millions of people voted “illegally” in this election. Voter fraud is a myth at any meaningful scale. To give an idea of how rare fraud is in elections, one 2014 study from Loyola Law School professor Justin Levitt found only 31 credible incidents of fraud in US elections since the year 2000 — out of more than a billion ballots cast. To claim there were millions of ballots illegally cast is careless and absurd.

But this is just one false claim of many, and Trump has given no indication that he will restrain his careless speech or improve his standards for evidence. He has used Twitter to tweet and retweet false and misleading information at a volume that has challenged the bandwidth of fact checkers. In many cases the fact checkers don’t get a word in before the false claim:

Donald Trump: "I won the popular vote if you deduct the millions of people who voted illegally" https://t.co/ZTLYTfQL3L — Washington Post (@washingtonpost) November 27, 2016

Trump has proven that he does not need traditional media access to spread information and disinformation across traditional mass media channels. This gives him the ability to frustrate, if not eliminate, other venues where press gatekeepers have traditionally enjoyed access. And even when he does grant access, what he says still gets blasted in 140-character soundbites. When he gave an interview to The New York Times last week, Times reporters tweeted his statements live.

When Trump becomes president, his Twitter account won’t just be the ramblings of a private citizen — it will be the remarks of the chief executive of the US government. And if his Twitter account is the most open part of his administration, the platform could effectively become the White House press office.