Donald Trump’s speech accepting the Republican nomination for president will probably go down as one of the most frightening pieces of political rhetoric in U.S. history.

Even for people who believe the danger of genuine authoritarianism on the U.S. right is often exaggerated, it’s impossible not to hear in Trump’s speech echoes of the words and strategies of the world’s worst leaders.

Trump had just one message for Americans: Be afraid. You are under terrible threats from forces inside and outside your country, and he’s the only person who can save us.

The scariest part is how Trump subtly but clearly has begun melding together violence against U.S. police and terrorism: “The attacks on our police, and the terrorism in our cities,” he said, “threaten our very way of life.”

This is the favorite and most dangerous message of demagogues across all space and time. After all, if we know our external enemies are deeply evil, and our internal enemies are somehow their allies, we can feel justified in doing anything at all to our internal enemies. That’s just logic.

And if anything, Trump’s speech is actually more terrific, fabulous and huge than those of previous fanatics, since he promises he’s going to fix everything overnight. “The crime and violence that today afflicts our nation will soon — and I mean very soon — come to an end,” Trump says. “Beginning on January 20th of 2017, safety will be restored.”

This use of fear to destroy democracy is so old that it’s described exactly in Plato’s Republic, written in Ancient Greece around 380 B.C.

Tyranny, says Socrates in The Republic, is actually “an outgrowth of democracy.” And would-be tyrants always in every instance claim to be shielding regular people from terrible danger: “This and no other is the root from which a tyrant springs; when he first appears above ground he is a protector.”

Trump said that he is going to “protect” Americans or some aspect of American life 13 times tonight.

That makes sense, since as he portrayed the world, we desperately need protecting:

Nearly 180,000 illegal immigrants with criminal records, ordered deported from our country, are tonight roaming free to threaten peaceful citizens. …

Egypt was turned over to the radical Muslim brotherhood. … Iran is on the path to nuclear weapons. …

This is the legacy of Hillary Clinton: death, destruction, terrorism and weakness. …

My plan will begin with safety at home – which means safe neighborhoods, secure borders, and protection from terrorism. …

I have joined the political arena so that the powerful can no longer beat up on people who cannot defend themselves. …

America was shocked to its core when our police officers in Dallas were brutally executed. … I have a message to every last person threatening the peace on our streets and the safety of our police: When I take the oath of office next year, I will restore law and order to our country. …

We must also address the growing threats we face from outside America. …

Men, women and children viciously mowed down. Lives ruined. Families ripped apart. … Only weeks ago, in Orlando, Florida, 49 wonderful Americans were savagely murdered by an Islamic terrorist. …

We Will Make America Safe Again.

As The Republic explains, leaders like this inevitably end up “standing up in the chariot of State with the reins in his hand, no longer protector, but tyrant absolute.” This is how liberty “passes into the harshest and bitterest form of slavery.”

The good news is that if you turn off cable news — apparently the only source of Donald Trump’s knowledge about the world — and go outside, you’ll find that the U.S. is probably safer today than it’s ever been.

Despite the misleading statistics Trump used again tonight, the rate of murder and crime overall remains far, far lower than in the past. You also don’t need to worry about ISIS: even after the massacre of 49 people in Orlando, it’s likely more Americans will be killed by bee stings in 2016 than by terrorism.

Nonetheless, anyone who knows anything about the past must be genuinely worried that a major party could nominate someone like Trump. As the German philosopher Hegel famously said 200 years ago, “What experience and history teach is this — that people and governments never have learned anything from history.”