Twitter has, for the first time, added a warning label to a tweet by President Donald Trump pointing out that what he said is inaccurate.

However, the social network was calling out Trump’s falsehoods about mail-in ballots — and was not taking action about Trump’s repeated use of Twitter to promote the unfounded conspiracy theory that MSNBC’s Joe Scarborough may have murdered a staffer when Scarborough as a congressman.

On Tuesday morning, Trump wrote in a two-part Twitter post, “There is NO WAY (ZERO!) that Mail-In Ballots will be anything less than substantially fraudulent. Mail boxes will be robbed, ballots will be forged & even illegally printed out & fraudulently signed.”

Trump also wrote, “The Governor of California is sending Ballots to millions of people, anyone living in the state, no matter who they are or how they got there, will get one. That will be followed up with professionals telling all of these people, many of whom have never even thought of voting before, how, and for whom, to vote. This will be a Rigged Election. No way!”

Later in the day, Twitter added a warning label to the two Trump tweets, saying “Get the facts about mail-in ballots.” The warning links to a page where Twitter explains why Trump is lying.

“Trump falsely claimed that mail-in ballots would lead to ‘a Rigged Election.’ However, fact-checkers say there is no evidence that mail-in ballots are linked to voter fraud,” the Twitter page debunking Trump’s lies says.

Twitter’s page also says, “Trump falsely claimed that California will send mail-in ballots to ‘anyone living in the state, no matter who they are or how they got there.’ In fact, only registered voters will receive ballots.” In addition, according to Twitter’s fact-check, “Though Trump targeted California, mail-in ballots are already used in some states, including Oregon, Utah and Nebraska.”

The warning label doesn’t show up in all contexts on Twitter (such as tweets embedded in a web page). On the fact-check page, Twitter links to stories from CNN, the Washington Post, the Hill and includes other tweets that explain why Trump was lying.

After Twitter applied the fact-check labels, Trump falsely claimed in a tweet that “Twitter is completely stifling FREE SPEECH” and issued a vague threat that “I, as President, will not allow it to happen!”

First, Twitter didn’t remove Trump’s false tweets: It simply provided links to factual information on the subject. More to the point, as a private company, Twitter is fully within its rights to enforce conduct and content guidelines about what’s allowed on the platform. The free-speech protections afforded by the U.S. Constitution’s First Amendment apply to government entities in the U.S., not private companies. According to Trump, “@Twitter is now interfering in the 2020 Presidential Election” because Twitter flagged his falsehoods about mail-in ballots.

In March 2020, meanwhile, Twitter applied a “manipulated media” label to a tweet from Trump’s head of social media of with a video of Joe Biden (which was retweeted by the president) that was deceptively edited to make it seem as if Biden admitted Trump’s re-election was inevitable.

In the case of political figures like Trump, Twitter provides special exceptions for tweets that would be violations for regular users but which would be in “the public interest” to leave up. In June 2019, Twitter announced a policy under which tweets by political figures that violate its regular policies would be displayed with a warning notice in front of tweets.

The warning labels Twitter applied Tuesday to Trump’s tweets fall under the company’s policy to flag posts that contain “disputed or misleading information,” adopted in response to coronavirus-related material.