The “Travel Ban” Decision, in One (Non-Snarky) Sentence

The U.S. has nearly unlimited power to decide when foreigners are admitted to the country, even based on factors (such as ideology, religion, and likely race and sex) that would be unconstitutional as to people already in the country.

Eugene Volokh|Jun. 26, 2018 11:47 am

There's a lot to be said about this morning's Trump v. Hawaii decision, and I will say little of it. But I do want to summarize what I think is the core legal principle behind the majority's constitutional position: The federal government may pick and choose which foreigners to let into the country (at least setting aside foreigners who have are already been granted residence), even based on factors -- political beliefs, religion, and likely race and sex -- that would normally be unconstitutional.

This used to be called the "plenary power" doctrine, referring to the principle that the government has essentially unlimited power when it comes to at least this aspect of immigration law, unlimited even by the Bill of Rights. It is not based on the constitutional text; textually, the First Amendment would apply to all exercise of Congressional authority, whether under the Commerce Clause or the District of Columbia Clause or the Necessary and Proper Clause under Congress's power over immigration. But, right or wrong, it is based on longstanding American legal history; and the majority adheres to that history.

Historically, this has even be used to authorize Congress to discriminate based on race (query whether the Court would today condemn this as "irrational"; more on that below). It has long been seen as authorizing Congress to discriminate based on country of citizenship, without investigation into whether such discrimination might actually be motivated by ethnic hostility. And, most relevant to today's decision, it was seen in Kleindienst v. Mandel (1972) as authorizing discrimination based on political ideology, which would otherwise be forbidden by the First Amendment. (Other past Supreme Court precedents are also consistent with Kleindienst, and some even go further in some respects, but for the sake of simplicity I will focus on Kleindienst here.)
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Congress -- and the President, to the extent Congress delegates some such power to the President (as historically it often has) -- gets to decide who comes into the country, with no substantial scrutiny under the Bill of Rights by the courts. One can of course agree or disagree with this, but that's the heart of the majority's position.