I have written repeatedly about the hard-left bias in the teaching of AP American History. I finally got tired of writing such posts and abandoned the beat.

But now, I learn that, beginning in 2020, many Advanced Placement students will be using an American History textbook that suggests President Trump is mentally ill and that depicts him and many of his supporters as racists. The book asserts that “[Trump’s] not very-hidden racism connected with a significant number of primary voters.”

What connected with a significant number of primary voters was Trump’s strong opposition to illegal immigration and his concern over terrorists entering the U.S. The textbook effectively characterizes these concerns as “not very-hidden racism” and those who share them as racists. This is controversial, to say the least. I consider it slanderous.

The textbook goes further. It says that Hillary Clinton supporters “worried about the mental stability of the president-elect.” Some did, or claimed to. But many Trump supporters worried about whether Clinton compromised our national security by criminally using a private email servers. Some McCain supporters worried about what they considered (with good reason) Barack Obama’s socialism and his undeniably communist mentor.

Does the textbook air these concerns? I doubt it.

The textbook clearly is using “Clinton supporters” as a device to plant the idea that President Trump is mentally unstable, a proposition for which there is no basis other than raw hatred of the man.

The book’s publisher defends its handiwork, saying that it underwent “rigorous peer review to ensure academic integrity.” No doubt.

The “peers” clearly share the blatant partisanship and mindless anti-Trumpism of the textbook’s author. If they didn’t hate Trump, they wouldn’t be peers. They would be academic outcasts.

The book’s hateful insinuations and assertions about Trump and those who voted for him are unacceptable in a text used to teach high school students American History. Any school in which the book is used should be the target of vigorous protests. The political blowback should be fierce.