At Columbia University, which has long borne witness to protests and dissent, the atmosphere has shifted under a new regime of policy changes ostensibly aimed at heightening security, according to CNN interviews with more than a dozen students and faculty.

Donald Trump has revoked visas for many students at elite American universities, raising concerns not only within the academic community but also among civil rights advocates. What do you need to know?

President Donald Trump’s visa crackdown is now hitting major schools across the US, with three Harvard University students and two recent graduates having had their student visas revoked. This comes amid Trump’s efforts to deport international students involved in pro-Palestine protests.