Purdue rescinds departmental graduate acceptance letters to over 100 students, mostly from China, under an unwritten university policy formulated in response to Trump administration pressure. A faculty quote: "when we’ve asked to get it in writing, [administrators] say they haven’t done it because then somebody could sue us." https://www.science.org/content/article/purdue-blocks-admission-many-chinese-grad-students-unwritten-policy, via https://news.ycombinator.com/item?id=46668801 (and as usual don't read comments there).