Far-right groups stockpiling guns and explosives, preparing for a violent overthrow of a government they deem illegitimate. Open antisemitism on the airwaves, expressed by mainstream media figures. Leading politicians openly embracing bigoted, authoritarian leaders abroad who disdain democracy and the rule of law.

This might sound like a recap of the past few years in America, but it is actually the forgotten story told in a remarkable new podcast, “Ultra,” that recounts the shocking tale of how during World War II, Nazi propagandists infiltrated far-right American groups and the America First movement, wormed into the offices of senators and representatives and fomented a plot to overthrow the United States government.

“This is a story about politics at the edge,” said the show’s creator and host, Rachel Maddow, in the opening episode. “And a criminal justice system trying, trying but ill suited to thwart this kind of danger.”

Maddow is, of course, a master storyteller and never lets the comparisons to today’s troubles get too on the nose. But as I hung on each episode, I couldn’t help thinking about Jan. 6 and wondering: Will that day and its aftermath be a hinge point in our country’s history? Or a forgotten episode to be plumbed by some podcaster decades from now?

When asked about the meaning of contemporary events, historians like to jokingly reply, “Ask me in 100 years.” This week, the committee in the House of Representatives investigating the Jan. 6 Capitol riot will drop its doorstop-size report, a critical early installment in the historical record. Journalists, historians and activists have already generated much, much more material, and more is still to come.

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In some ways, it is understandable that this moment was treated as an aberration. The America First movement, which provided mainstream cover for extremist groups, evaporated almost instantly after the attack on Pearl Harbor. Maybe it was even necessary to forget. When the war was over, there was so much to do: rebuild Europe, integrate American servicemen back into society, confront the existential threat of nuclear war with the Soviet Union. Who had the time to litigate who had been wrong about Germany in the 1930s?

Even professional historians shied away from this period. Bradley Hart, a historian whose 2018 book, “Hitler’s American Friends,” unearthed a great deal of this saga, said that despite the wealth of documentary material, there was little written about the subject. “This is a really uncomfortable chapter in American history because we want to believe the Second World War was this great moment when America was on the side of democracy and human rights,” Hart told me. “There is this sense that you have to forget certain parts of history in order to move on.”