This is very scary. I’m an American community college instructor in Silicon Valley who does research with domestic and international colleagues; in fact, I will be in Japan this summer as a visiting researcher. If people could be denied entry to the United States over harmless political opinions shared electronically, then this hurts our ability to collaborate in-person with foreign researchers in the United States, and this also hurts our ability to hold academic conferences here.

It’s one thing if the scientist made threats or advocated overthrow; that is not protected free speech. But if it’s just an opinion or even name-calling, then this denial of entry is flatly wrong and flatly un-American.

Perhaps it’s time for prominent US academic conferences with international attendees to move to Canada, France, Japan, or some other place where scientists and science in general are not under attack by their government.

“Free speech” has always been about protecting people against exactly this, but since they have spent almost a decade destroying the meaning of the phrase, they can now get rid of the freedom it entails.