The forthcoming young adult novel “Blood Heir” would not strike most readers as racist. Its Chinese author, Amélie Wen Zhao, was born in Paris and grew up in Beijing. Its fantastical plot — a princess with magic powers flees her father’s palace after his murder — draws inspiration from Russian history, particularly the Anastasia mythos, and its cast of characters is diverse.

Yet, in January 2019, a small number of far-left thought-enforcers launched a withering social media mob campaign to discredit “Blood Heir” on the baseless grounds that it was ignorant, racist, and reactionary. In the short term, they succeeded.