American liberals have a corrosive illiberalism problem. And Donald Trump is exploiting it.

We’re living through a sharply illiberal moment in America. Following through and expanding on the logic of anti-discrimination law, which seeks to protect distinct classes of citizens from unequal treatment in public accommodations, the activist left increasingly uses a mixture of bureaucratic regulations, protest, and public disruption to get an ever-growing list of topics relegated to the category of the undiscussable. These topics must not be raised because talking about them produces offense, which amounts to a form of discrimination. Those in the University of California system who are trying to rule anti-Zionism out of bounds are merely expanding this logic one further step, to get Zionists added to the list of groups officially protected from offense.

An alarmingly large swath of the right, meanwhile, has embraced an illiberalism of its own, with the shockingly successful presidential campaign of Donald Trump its boldest expression yet. A lot has been written about the economic sources of Trump’s rise, especially the decline and frustrations of the white working class. But the visceral hostility of many Trump supporters to “political correctness” is also a significant factor. Trump has openly attacked Mexican immigrants, Muslims, and other groups during his campaign, and his admirers treat these attacks as a welcome sign that as president he wouldn’t allow himself to be pushed around by those who would deny his right to think and say whatever he wants.