First there was one democracy —then 10, then 20.

There were some setbacks, but people really seemed to want democracy.

And eventually, most of them got one.

But 15 years ago, democracy stopped spreading, and it might not pick back up again.

Even some places that seemed safely democratic turned out not to be.

And people are even getting worried about established democracies like the U.S.

So is there something wrong with democracy?

I'm Max Fisher.　

I'm Amanda Taub.

We're journalists at The New York Times.

And this is The Interpreter.

We can measure democracy kind of like a health score.

Over here, there are full democracies like the United States (US).

And over there are dictatorships like North Korea.

So the further left a country is, the less democratic it is, and the further right a country, the more democratic it is.

Now let's see what happens when we add how rich the countries are.

The higher on the graph, the richer the country, and the lower on the graph, the poorer the country.

Generally, countries have moved up and right.

As they got richer, they became more democratic.

You've got your Englands, your Latvias, your Indonesias.

You see a pattern?

Countries getting richer.

Countries getting more democratic.

But look at countries like China and Saudi Arabia.

They got richer, but never got more democratic.

Look at Russia and Venezuela.

They got democratic, but then backslid, which wasn't supposed to happen.

So what's going on?

China looked exactly like places we thought would become democracies next.

They built up the rule of law, civil society, and some institutions.

Normally, those are the building blocks that eventually add up to democracy.

But they were really designed to make citizens just happy enough to protect the authoritarian system from the will of the people.

And whenever the government feels like it could lose control, it uses the other side of its strategy: violent oppression and coercion.

We're seeing this in more places where dictators are learning how to stop democracy from forming.

And at the same time, some elected leaders are developing their own playbook for pulling democratic systems down from within.

A handful of seemingly established democracies are sliding back towards dictatorship.

These countries didn't have coups or invasions.

In each case, voters elected strongman leaders who dismantled their democracies from within.

Venezuela had been democratic for 40 years, then Hugo Chavez rose on a message that only he spoke for the people.

People cheered as he accrued power for himself, jailed his opponents and tore down the democratic institutions that constrained him.

And when the dust settled, Chavez was unchecked.

Society descended into chaos that is getting worse every day.

Other elected leaders are using similar tactics, but always bit by bit— in ways that aren't obvious and might even be popular at the time.

One of the most powerful forces that can turn people against democracy is polarization.

When people feel scared enough of their political opponents, it feels more important to protect their side than it does to protect democracy.

Leaders can exploit that fear.

So if you're Russian and you support Putin, you might blame society's problems on gay people or nefarious Western plots.

If you're Turkish and support Erdogan, you fear the secular elites will impose military rule.

And we're seeing that kind of polarization and fear start to take hold in established democracies.

"You are a racist, no good American."

"I was just called a racist."

Could it happen in the United States?

It still feels impossible.

And it might be.

So far, the system is resilient.

But the warning signs are here.

Polarization.

Populism.

Distrust of institutions.

A desire for strongman leaders to smash the system.

These things don't necessarily mean that democracy is doomed.

But they show that in times of social stress, even a free people can dismantle their own democracy without realizing they're doing it.

Democracy is still a pretty new system of government.

That century-long trend might not have been a trend at all.

Just a few one-time moments that we mistook for inevitability.

We want to believe it will last forever, but we can't be sure.