In an act of sublime idiocy, the San Francisco school board has decided to paint over a mural of George Washington in a local high school.

To those who know the mural’s history, this is a consummate act of the microaggression revolution devouring its own in a frenzy of ignorance.

The mural is not a paean to Washington the military hero or the first president of the Republic. This is not Washington crossing the Delaware or on bent knee at Valley Forge seeking divine guidance.

The picture depicts Washington standing over his slaves picking cotton while a group of colonizers pass by the body of a dead Indian.

In most other American cities, conservative forces would have had their own reasons for tearing down the mural. But then this is San Francisco, a town that has long had a powerful liberal to militant left political nexus.

The artist was Victor Arnautoff, Russian immigrant, devoted communist, and colleague of fellow revolutionary Diego Rivera. Like Rivera, Arnautoff was interested in art as a critique of society. Rivera’s dynamic murals, some of which are in San Francisco, are probably next on the burn list.

Arnautoff’s Washington is American history depicted at its worst, showing not only an incongruity of values but also nothing about its virtues. If the standard rendition is to glorify Washington, this is a work that turns Washington and the revolutionary experience on its head.

For an old academic like me, this is a teaching moment. There is the triumph of a society that permits the freedom of expression to allow such a critique. Could you remotely conceive of The Boss, Stalin, permitting the creation of a mural depicting starving Ukrainians, mass executions, and brutal scenes of survival from the Gulag?

For all of Arnautoff’s revolutionary and communist zeal, it is America that permitted him to blight and question sacred institutions. There is no communist government on the face of the planet that would not have had him executed for such an affront.

In America, Arnautoff was viewed as an important artist, commissioned by the government’s Works Progress Administration, and praised for daring to reveal the dark side of America.

But I doubt that is the history lesson the San Francisco school board fears.

Rather, in an era of heightened lunacy where the mere accusation of racism sends everyone to prove they are not in league with the devil and have never danced naked beneath the full moon, the offending attributes are the depiction of blacks picking cotton and Indians stepped over to make way for the expansion to the new frontier.

These accurate but alleged “painful” reminders of part of our history are no longer to be tolerated, not even in uber-liberal San Francisco, where political correctness has become just another form of Orwellian groupthink administered by people who, by calling themselves educators, have made a mockery of the long torturous history of humanity to free itself from tyrants, secular and religious.

It will cost the San Francisco school district some $600,000 to complete this secular bonfire of the vanities. It might want to consider that with some 30% of its black students not finishing high school and an almost equal proportion of white and Latino students in the same dilemma, there are better uses for this money.

Abraham H. Miller is an emeritus professor of political science. He lives in the San Francisco Bay Area.