HAMBURG, Germany — It may well be that Germans have a special inclination to panic at specters from the past, and I admit that this alarmism annoys me at times. Yet watching President Trump’s “Stop the Steal” campaign since Election Day, I can’t help but see a parallel to one of the most dreadful episodes from Germany’s history.

One hundred years ago, amid the implosions of Imperial Germany, powerful conservatives who led the country into war refused to accept that they had lost. Their denial gave birth to arguably the most potent and disastrous political lie of the 20th century — the Dolchstosslegende, or stab-in-the-back myth.

Its core claim was that Imperial Germany never lost World War I. Defeat, its proponents said, was declared but not warranted. It was a conspiracy, a con, a capitulation — a grave betrayal that forever stained the nation. That the claim was palpably false didn’t matter. Among a sizable number of Germans, it stirred resentment, humiliation and anger. And the one figure who knew best how to exploit their frustration was Adolf Hitler.

Don’t get me wrong: This is not about comparing Mr. Trump to Hitler, which would be absurd. But the Dolchstosslegende provides a warning. It’s tempting to dismiss Mr. Trump’s irrational claim that the election was “rigged” as a laughable last convulsion of his reign or a cynical bid to heighten the market value for the TV personality he might once again intend to become, especially as he appears to be giving up on his effort to overturn the election result.

But that would be a grave error. Instead, the campaign should be seen as what it is: an attempt to elevate “They stole it” to the level of legend, perhaps seeding for the future social polarization and division on a scale America has never seen.