Donald Trump and Vladimir Putin are buddies. Trump often praises Putin and has been known to share intelligence information with the Russians. The two are also soulmates and allies: they attack liberal democracy at home and undermine the rule-based international political order. Hitler and Stalin were also allies once. They joined forces 80 years ago to carve up Poland, but two years later they were at each other’s throats.

Can it happen again? Researchers at Princeton think it can—a nuclear confrontation between Russia and the US is increasingly likely. Stunts like Trump’s alleged offer to President Volodymyr Zelensky to exchange U.S. military aid for dirt on his political opponents show both how US institutions have been supplanted in favor of Russian-style “hand-management” and how the two friends could fall out.

Historical parallels are dangerous. History never repeats itself exactly—just as no human being is exactly the same as another—and the devil is in the nuance. However, looking back at history is the only way we can make sense of the present and predict the future even though such analysis and forecasts are far from perfect.

Our own age is increasingly reminiscent of the 1930s. It has featured an economic debacle similar to the Great Depression, out of which a number of authoritarian figures eventually emerged. It seems that in a period of economic uncertainty the masses lose confidence in existing institutions and become attracted to small, narcissistic, unscrupulous men who claim without any evidence that they have all the answers.

The 1930s were the age of dictators, but it was also the age of ideologies. Communists and national socialists believed they had discovered how the world works and murdered millions to stage their cruel social experiments. Ideologies indeed appear to be dead, and we’re once again stuck with more or less traditional religions, but this doesn’t alter the picture. There are still small-minded, self-obsessed, truculent men who are playing great national leaders and are dismantling existing national institutions.

Putin is obviously no Stalin. He has no illusions about ushering a new era or building a universal paradise on earth. All he seems to be interested in is accumulating as much hidden wealth as possible, staying physically fit and holding on to power.

But he’s presiding over a system built by Stalin, which has changed very little since the tyrant’s death some 65 years ago. Like Stalin, he became Russia’s ruler before the Great Recession but the nature of his power changed radically after he came back as president in 2012. And he grew out of the most important and resilient Bolshevik institution, which began as the Cheka, went through a dozen different names and is now known as the FSB.

Russia’s system as built by Stalin has two main characteristics: first, while it has all the trappings of civil society—the Constitution, the Parliament, courts, the press, professional associations—none have an iota of influence over the dictator.

Second, Russia’s system is built on the principle of Darwinian natural selection, and it promotes the most venal, dishonest, unscrupulous and immoral members of society into the highest positions of government and in general, tends to catapult such characters to great social prominence.

It has been obvious that no checks have ever been placed on Putin’s power. The reason he has not resorted to Stalin-like mass repressions is because he has not needed to — as yet — in order to achieve his goals, which are listed above.

Now that his power has been even moderately threatened by Alexey Navalny’s “intelligent voting”, showing that a large number of people essentially gave their votes to the opposition leader, Putin is lashing out. Innocent people are beaten up by his uniformed thugs and put in jail, and parents are in danger of having their kids taken away. All of that should be familiar to anyone who knows anything about Soviet history. The scandalous case of a falsely convicted actor who has been rescued by a widespread outcry means nothing. There is no doubt that Putin will drown Russian in blood if he feels seriously threatened.

If you still think that he has more respect for the law or human life, you need to look no farther than Beslan or Eastern Ukraine.

Trump is certainly no Hitler. But we have been conditioned to think of Hitler and his entourage, men like Goering, Ribbentrop and Goebbels, as monsters. In reality, only their deeds were monstrous. The men themselves were evil clowns—not unlike Trump, Pompeo, Bolton and Sean Hannity.

Many people around the world were shocked and dismayed when Hitler came to power. How was it possible that the Germans, the highly cultured, civilized nation, the land of Goethe, Heine and Schiller, had elected this half-literate buffoon as their leader and are reading his graphomaniac drivel as though it was a work of some great philosopher?

This is what America’s many friends around the world are asking: how is it possible that the world’s oldest democracy, the birthplace of liberty and a shining city upon the hill has fallen for a Trump? How did the vaunted iron-proof system of checks and balances devised by the Founding Fathers and safeguarded by the world’s greatest Constitution manage to crumble so ignominiously? Why did American institutions fail so readily under the onslaught from a failed businessman and a talk show host? How come the American political establishment become the assemblage of scoundrels, cowards and incompetents?

Hitler and Stalin hated liberal democracy for ideological reasons. Putin and Trump hate it too, but their hatred is stripped of any ideological underpinnings. They hate it because it stands in the way of their authoritarian power and, to bring matters down to earth, makes it more difficult for them and their entourage to enrich themselves from the public till.

But they’re not content to abolish or undermine democratic institutions at home: the courts, the free press and government agencies. They do not limit themselves to corrupting law enforcement agencies and perverting their function. Exactly like Hitler and Stalin, those two are undermining the rule-based international world order. Putin’s agents are meddling in democratic elections wherever they can, while Trump is attacking America’s democratic allies and hollowing out international institutions most of which were set up under America’s leadership.

Besides being soulmates, a certain point, Hitler and Stalin were allies, too. Eighty years ago they dismembered Poland and started World War II. But there’s no honor among thieves. They had a falling out and the war between them became by far the bloodiest segment of the world’s bloodiest conflict. Will history repeat itself?