Having fought through them to get to an airport today to fly back to SFO, I’m less sympathetic than I was earlier to the protesters.
But seriously, I don’t think the ban is a good idea as a matter of policy. I would rather the government have let everyone with an existing visa into the country. Those with permanent-resident status have a right to have their case adjudicated before they can be expelled. The administration could have declared a pause in immigration from these nations while it more carefully re-examined how to scrutinize immigrants coming in from nations with significant terrorism problems. This is basically what the U.S. did toward a few nations right after 9/11.
But I think that as a matter of law, rather than of policy, the government can cut off immigration from any country if the president determines there to be national-security threat. This isn’t even a claim of presidential power, as Congress delegated that power to the president in the immigration laws. There are all kinds of issues with the implementation of this new policy, but I think that the president can use the power given to him by Congress in this way. Congress, of course, could override the Trump ban if it so chooses, or pressure him to withdraw it in a variety of ways, such as refusing to pay for his proposed $12 billion border wall.
Some people argue that it is unconstitutional or illegal to favor some nations over others. But this is inherent in our immigration laws, which from the beginning gave greater quotas for immigrants for some nations rather than others. Our first federal immigration law was called the Chinese Exclusion law for a reason, and the Supreme Court case upholding the law is known as the Chinese Exclusion Case for a reason. I wish the U.S. had not passed such laws in the late 19th century, but it seems undeniable that the nation can do it legally. I don’t support the use of immigration laws in a way that allows the venting of racist impulses. But the U.S. also has the right to favor some nations over others in immigration. The U.S. could grant more slots to our allies in Europe and Asia, and cut off immigration from Russia and China, because the former support our interests and the latter do not.