Thomas Weber is the author most recently of "Becoming Hitler: The Making of a Nazi" and professor of history and international affairs at the University of Aberdeen.

Adolf Hitler, center, and members of the Nazi party march through downtown Munich on Nov. 9, 1937, to commemorate the failed attempt on Nov. 9, 1923, by Nazis to take power in Bavaria. (AP)

After Adolf Hitler’s warriors had laid waste to the Soviet Union during World War II, the secret collusion of Russian nationalists with the German leader in the 1920s became an embarrassment. In the 70 years since Hitler’s defeat, Russian nationalists have done everything possible to conceal their onetime belief that he could aid them in undoing the October Revolution of 1917 and making Russia great again.

There are enough parallels here — collusion with Russia, an obsession with national greatness — to tempt people to entertain yet another ill-judged Hitler-Trump comparison.

Yet the real significance of Hitler’s secret Russian collusion does not lie in shedding light on the challenges President Trump poses to American democracy, but on the strategic challenge that Russia poses to the world. For there has been a line of continuity from the collusion of Russian nationalists with Hitler in the early 1920s, to Joseph Stalin’s secret pact with the Nazi leader in 1939, to President Vladimir Putin’s conduct in Ukraine and his interference in the elections in the United States.

In all cases, Russia has ruthlessly pursued its self-interests with few concerns about the costs to human life and geopolitical repercussions. If it’s ostensibly good for Russia, it’s full steam ahead, regardless of the consequences for everyone else.

While Russians have sought to conceal this past, not all traces of their collusion with Hitler in the early years of his rise have been erased from history. One of the surviving pieces of evidence of Hitler’s secret Russian contacts is a September 1923 photograph. It depicts Hitler chatting and smiling with none other than Grand Duchess Victoria Feodorovna of Russia. Less than six weeks later, on the night of Hitler’s attempted coup d’état, Victoria — the wife of Grand Duke Kirill Romanov, one of the pretenders to the Russian throne — stayed at the house of Hitler’s chief foreign policy adviser, Max Erwin von Scheubner-Richter.

Earlier that year, Hitler met with Nikolai Snessarev, one of the aides to Kirill Romanov and a former member of the Saint Petersburg City Duma. Snessarev believed, as he put it in his 1923 book “Die Zwangsjacke” (“The Straight Jacket”), “Fascism offers the first realistic possibility for European civilization to save itself from its imminent downfall.” Grand Duke Kirill himself, meanwhile, secretly supported Hitler with large sums of money.

On the few occasions that historians have taken Hitler’s Russian contacts seriously, they have tended to raise the question as to whether National Socialism had Russian roots. Yet the real meaning of Hitler’s secret Russian collusion lies somewhere else.

Snessarev’s book provides vital clues as to why Hitler and Russian nationalists were eager to work together. Kirill’s aide wrote that only an alliance between Germany and Russia could rescue Europe: “Unified Germany, and unified Russia. Is this not the beginning of a realization of the greatest and most humane dream of our time — the unification of the two youngest, but also the most vital peoples of the old world?”

Germany’s future dictator agreed. Ever since the moment of Hitler’s sudden politicization and radicalization in 1919, he had sought to understand how Germany could be put on equal footing with the Anglo-American world. The ratification of the Versailles Treaty, the punitive peace accord that brought World War I to an end, had been the moment of Hitler’s political epiphany, as it was only then that a realization of defeat in the war set in.

In the moment of his political awakening, he set himself two questions: How could Germany have lost the war? More importantly, how would Germany have to be recast to survive in a rapidly changing world dominated by a small number of super powers?

His answers would guide him until the day he died in the ruins of Berlin in 1945: Germany’s chief domestic weakness stemmed from the supposedly pernicious and lethal influence of the Jews, and its chief external weakness was insufficient territory, manpower and resources.

Initially, Hitler simply did not believe that Germany would be able to overcome the sources of its external weakness on its own, which made Snessarev’s ideas so attractive to him. Germany, Hitler concluded, could only survive and compete with the Anglo-American world if it entered into a permanent and all-encompassing alliance with a restored Tsarist Russia.

This realization brought him into the fold of Tsarist exiles living in Bavaria, who — just like Hitler — believed that on their own they would not be able to rise from the ashes. It was Hitler, not Russia, who eventually ended the collusion.

Russia’s many apologists in Europe and the U.S. should wake up to the common denominator visible here in Russian conduct past and present: a geopolitical pursuit of Russia’s national interests, marked by a disregard for human life and dignity.

Russians themselves should note the unwise and counterproductive nature in which their geopolitical goals have been pursued and ultimately turned on their own motherland. The graveyards holding more than 20 million Soviet citizens killed by Hitler’s men should act as somber warning about the dangers of the pursuit of a hazardous geopolitical strategy.