Donald Trump’s response to Donna Brazile’s “rigged” primary claim is terrifying.

As soon as Politico published an explosive excerpt from Democratic strategist Donna Brazile’s new book, in which she alleges that Hillary Clinton “rigged” the 2016 Democratic primary, a series of incendiary tweets from the president became inevitable. After all, Trump is obsessed with returning to the 2016 election, his last and only real political triumph, and with making a bogeyman of Hillary Clinton, one of only a handful of opposition figures who can compete with him in terms of unpopularity. But Trump’s response, in which he repeatedly calls for the Department of Justice to investigate Clinton, is still alarming.

This is familiar territory for Trump, who repeatedly tried to drive a wedge between Clinton and Sanders supporters (with questionable success) during the 2016 election. Drawing in Elizabeth Warren, whom he refers to with the racist term “Pocahontas,” could be seen as an extension of this strategy to a leading 2020 contender.

But whatever political ends Trump has in mind are beside the point. Yes, this is an empty threat—Trump doesn’t have the power to order such an investigation and there’s no reason to believe that the DOJ is going to start targeting Clinton. But what’s important is that Trump has faced no consequences for repeatedly threatening to prosecute his political opponents, a strategy that he’s sure to return to, with the aid of allies in the Republican Party and conservative media, again and again over the next two years. It’s destructive and authoritarian but it’s become normal over the last year and a half.