The most important part is that this is the first time we're seeing the effects of a new law, (1) giving CBP officers discretion about who to deny, even if they

The most important part is that this is the first time we're seeing the effects of a new law, (1) giving CBP officers discretion about who to deny, even if they have valid paperwork, (2) not requiring them to give a reason why they were denied > A critical factor in the recent deportations may have been a directive issued in May 2020 by then-President Donald Trump. It gives CBP the authority to deny entry to Chinese graduate students and postdoctoral scholars who have been supported by Chinese institutions carrying out a 2017 government edict that endorses acquiring foreign civilian technologies that could also have military uses. However, there’s no official list of such entities or of the relevant technologies.