Former Maryland Gov. Martin O’Malley likened President-Elect Donald Trump and his millions of supporters to Nazis and members of the Ku Klux Klan in a tweet late Saturday evening.

It all began when the failed 2016 Democratic presidential candidate took to Twitter to add his voice to the spat between Trump and civil rights icon Rep. John Lewis (D-Ga.) that blew up over the weekend. Lewis made waves when a clip from his interview on NBC News’ “Meet the Press” was released Friday. In the clip, Lewis said that he does not view Trump as a “legitimate” president because of the reports on Russian hacking. He also added that it will be “almost impossible” for him to work with Trump and find common ground.

“Now is not the time for reconciliation. Dietrich Bonhoeffer didn’t reconcile with the Nazis. MLK didn’t reconcile with the KKK. Now we fight.”

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In response, O’Malley tweeted Friday evening that he supported Lewis’ doubts about the election’s integrity and results.

“@repjohnlewis is right. Trump wasnt popularly elected. A fascist candidacy based on racist fears & Russian help should never be legitimized,” O’Malley initially tweeted.

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Following that tweet, O’Malley appeared as the keynote speaker for the Utah Democratic Party’s annual gala Saturday. Then, building off of his aggressive earlier tweet, the former Democratic presidential candidate tweeted two pictures of the event with the disturbing caption: “Now is not the time for reconciliation. Dietrich Bonhoeffer didn’t reconcile with the Nazis. MLK didn’t reconcile with the KKK. Now we fight.”

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Many Twitter users responded rapidly and harshly to O’Malley’s characterization.

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“Nazi’s killed millions, KKK killed thousands, Trump killed no one. You have zero credibility. You’re sick to compare them,” one Twitter user said.

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“Are you out of your mind? Comparing Trump and his supporters to Nazis damages your side significantly more than his,” another person tweeted.

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“Right, just call everyone you disagree with Nazis. That’s the winning strategy that got you here,” another tweeted.

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“Martin O’Malley considers the 84% of American counties who voted for Trump to be Nazis and KKK,” said another.

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Even Jake Tapper, host of CNN’s “State of the Union,” seemed troubled by O’Malley’s words and entered the fray, asking, “@MartinOMalley what exactly do you mean by ‘fight,’ here, governor?”

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O’Malley’s aggressive stereotyping and “fighting words” certainly don’t promote the unity and healing that other Democrats have called for in the wake of a bitter presidential election between Trump and Democratic nominee Hillary Clinton. Although Sen. Joe Manchin (D-W.Va.) said that he has great respect for Lewis, he said Sunday on CBS’s “Face The Nation” that Lewis was wrong to question Trump’s legitimacy.

“I just think that was uncalled for. I just wish that rhetoric would tone down from both back and forth,” Manchin said. “That’s what we have to stop.”