“Universities are to Republicans what guns are to Democrats” is a neat summary from Princeton University professor Greg Conti of the political battle lines in the United States’ erupting campus culture war. The resignation this week of Harvard University president Claudine Gay is the latest event in a chain reaction that began last month in Washington.

When the presidents of three of the world’s most prestigious universities were unable to tell a House of Representatives committee hearing whether calling for the genocide of Jews would violate their institutions’ code of conduct, all the long-harboured suspicions of American conservatives about the US higher education system were confirmed.