A demagogue getting his people all worked up. What could go wrong?

At his rally on Thursday night in Indiana, President Trump unleashed his usual attacks on the news media, but he also added a refrain that should set off loud, clanging alarm bells. Trump didn’t simply castigate “fake news.” He also suggested the media is allied with special counsel Robert S. Mueller III’s probe — an alliance, he claimed, that is conspiring not just against Trump but also against his supporters.

“Today’s Democrat Party is held hostage by left-wing haters, angry mobs, deep-state radicals, establishment cronies and their fake-news allies,” Trump railed. “Our biggest obstacle and their greatest ally actually is the media.”

In case there is any doubt about what Trump meant by the “deep state” that is supposedly allied with the news media, Trump also lashed out at the FBI and the Justice Department, claiming that “people are angry” and threatening to personally “get involved.”

Robert D. Chain, who was arrested this week for allegedly threatening to murder journalists at the Boston Globe while mimicking Trump’s language, also connected Mueller’s investigation to the media. “You’re the enemy of the people, and we’re going to kill every f–––ing one of you,” Chain snarled into one employee’s voicemail, according to FBI documents. “Why don’t you call Mueller, maybe he can help you out.”

Trump surely knew about this arrest when he repeated his attacks on the news media Thursday night — and when he connected the media to the Mueller investigation as part of a grand conspiracy against him and his voters.

Periodically in this country, whenever there is violence with a political cast, or whenever political rhetoric strays into something more menacing than usual, we hold debates about the tone of our politics and their capacity for incitement. Whether rhetorical excess can be blamed for violence or the threat of it is a complicated topic with no easy answers. But even so, in most or all of these cases, whichever side is culpable, most of our elected leaders on both sides have used their prominence to calm passions in hopes of averting future horrors.

This time, something different is happening. At this point, there is no longer any denying that Trump continues to direct incendiary attacks against working members of the free press even though his own language is being cited by clearly unhinged people making horrifying death threats against them.

Trump’s assaults on the media are different in another way, too. Previous presidents have tangled with the press, most notably Richard Nixon, who sicced his vice president on the TV networks. But as I discuss in my forthcoming book, even these presidents maintained a grudging acceptance of the news media as an adversarial mechanism of accountability that legitimately informs the public debate and thus retains a vital institutional role in our democracy.

Trump simply does not accept this at all. He is trying to destroy this foundational set of ideas in the minds of his supporters. And it seems to be working.