The Washington Post has created a nifty tool designed to address one of the novel problems of our political era: a president-elect who persistently uses Twitter to spread lies. A web-browser extension for Chrome and Firefox, RealDonaldContext annotates some of Trump’s tweets with fact-checking from the Post. For instance, last month Trump tweeted, “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.” Below that, if you use the extension, is a note saying, “This is incorrect or false,” with this explication: “Trump didn’t win in a landslide in any sense—but more importantly there is absolutely no evidence that there were a significant number of votes cast illegally, much less ‘millions’ of them.”

RealDonaldContext meets a genuine need, given the importance tweeting plays in Trump’s media strategy and the frequency with which he lies. Trump’s authoritarianism is manifest in his attempt to impose a false reality on the world, which will become all the more dangerous when he assumes power. Thus, fact-checking his tweets is not only essential journalism, but an act of resistance—a reminder that Trump can’t make a lie come true by fiat alone.

Yet fact-checking, while necessary, is also only a partial solution. Trump’s core supporters, and the Republican Party that has decided to appease them, have proven willing to swallow his lies wholesale; they are immune to fact-checkers. Moreover, the problem with Trump’s tweets isn’t just that they often contain falsehoods, but that they are deliberate provocations with the potential to cause real conflict.

Consider Trump’s tweets after China seized a U.S. underwater drone:

China steals United States Navy research drone in international waters - rips it out of water and takes it to China in unprecedented act. — Donald J. Trump (@realDonaldTrump) December 17, 2016

We should tell China that we don't want the drone they stole back.- let them keep it! — Donald J. Trump (@realDonaldTrump) December 18, 2016

The Post annotated the first tweet by noting that the act was not unprecedented: “There have been other instances in which the Chinese have seized American military property. In 2001, following a collision with a Chinese fighter, an American spy plane was forced to land in China where it and its crew were held for days.” This annotation is useful enough, but it hardly addresses the real problem: that Trump is trying, even before assuming office, to turn a minor diplomatic scuffle into a major crisis.