If you read only one thing today, it has to be Peggy Noonan's important Wall Street Journal column arguing that there is "a whiff of China's Cultural Revolution in the air."

The comparison is Chairman Mao's Cultural Revolution, when people were paraded through the streets to derision wearing dunce caps for expressing the "wrong" ideas.

For Mao, launching the Cultural Revolution was better than admitting that his policies were leading to famine.

Noonan writes:

The air is full of accusation and humiliation. We have seen this spirit most famously on the campuses, where students protest harshly, sometimes violently, views they wish to suppress. Social media is full of swarming political and ideological mobs. In an interesting departure from democratic tradition, they don’t try to win the other side over. They only condemn and attempt to silence.

The spirit of the struggle session is all over Twitter . On literary Twitter social-justice warriors get advance copies of new books and denounce them for deviationism—as insensitive, racist, appropriative, anti-LGBTQ. Books on the eve of publication have been pulled, sometimes withdrawn by authors who apologize profusely. Everyone’s scared. And the tormentors are not satisfied by an apology. They’re excited by it and prowl for more prey.

. . .

Joe Biden understands the moment. He quickly apologized last week after calling Vice President Mike Pence “a decent guy.” Progressive Cynthia Nixon denounced Mr. Pence as “America’s most anti-LGBT elected leader and asked Mr. Biden to “consider how this falls on the ears of our community.” “You’re right, Cynthia,” he quickly responded.

All the Democratic candidates have apologized for something. Elizabeth Warren is abjectly sorry she took a DNA test.

Leaders of great liberal newspapers are in constant fear because so many of their readers—and writers—are more doctrinaire in their views, and angry. The struggle session is in the internal chatroom.

Interestingly, while an increasingly large pool of people end up being silenced because of all sorts of minor infractions of the PC code, one person has escaped censure and triumphed for genuinely disturbing anti-Semitic remarks.

Just don't slip up and say that Mike Pence is a decent guy.