Early last year, the investigative journalist Jodi Kantor was asked to give the commencement address to students at Columbia University in New York. The place was in chaos – amid continuing pro-Palestinian protests students were expelled, or arrested and detained by immigration officials, while President Trump had ordered a $400m withdrawal of federal funding (which was later reinstated as part of a settlement with the administration). Kantor was “horrified” to see what had happened at Columbia – her alma mater, where she was sacked from her first journalism job at the student paper– “a place and campus I loved, a...