The left-wing protest movement sweeping the country has been decades in the making, fueled in part by liberal college campuses, Wall Street Journal columnist Dan Henninger said Thursday.

Speaking to host Ed Henry on "America's Newsroom," Henninger said many Americans have been "stunned" to see protesters calling for monuments to Presidents George Washington, Thomas Jefferson and Ulysses S. Grant to be removed.

"They can't imagine where this came from," said Henninger, who argued that the "seeds of cancel culture" were planted on campuses for the last 30 years and mostly ignored.

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"It started on campuses when they enforced and instituted speech codes, which forbade a certain amount of words to be said by people. University presidents were complacent in that. Then they denied tenure to conservative professors who were balanced against groupthink.

"Then when the student started to attack their own liberal professors as racists, the universities stood aside, as did their liberal colleagues, and let that happen, too. That was the seeds of cancel culture, the irrational anti-history that we are seeing right now. Liberals in positions of leadership in our institutions stood by and let that happen," he continued, adding that those voices are "taking over" the Democratic Party.

"The progressives are saying 'you work for us, get out of the way, Joe Biden, get out of the way, Nancy Pelosi, we are taking over.' And people like Nancy Pelosi are basically saying 'no problem.'"

In his latest op-ed, the deputy editor of the Wall Street Journal editorial page described the movement as "smiley face liberalism." Henninger said "the quick collapse of America’s elites under this left-wing offensive is striking and a historic event," but questioned whether a backlash is coming.

"Will it last? I think people across the political spectrum are shell-shocked by the events of these weeks, especially the Taliban-like smashing of monuments and the embrace of lawlessness as an official ideology, with no credible pushback from Joe Biden or other prominent Democrats. But if history teaches us anything, it’s that the American electorate won’t be pushed around permanently," he wrote.

Meantime, BET founder Robert Johnson, in an interview Wednesday with Fox News Digital, blasted those who are toppling Confederate statues and other monuments across the nation as "borderline anarchists" -- while challenging the notion that black Americans support this.

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Johnson, who became the country's first black billionaire in 2001, has made a $14 trillion pitch for reparations to descendants of slavery. But he said the movement to take down statues, cancel TV shows and fire professors does nothing to close the wealth gap that has persisted since slavery.

It's "tantamount to rearranging the deck chairs on a racial Titanic," Johnson told Fox News. "It absolutely means nothing."