In Mullin v. Al Otro Lado, Justice Thomas concurred separately in part on the ground that the President has inherent authority to exclude aliens. I found this interesting because I know that Judge Augustus Hand contested this claim in an opinion he wrote in 1921. (Justice Robert Jackson relied upon that opinion, United States v. Western Union Tel. Co., in Youngstown.) Here, FWIW, is what A. Hand said in the relevant passage:
“Why does not the President, in the absence of any act of Congress, have the right to refuse to admit foreigners to our shores, and to deport those aliens whose presence he regards as a public menace? While the prerogative of the British Crown in respect to the admission and deportation of aliens is not clearly ascertainable, its right, in the absence of an act of Parliament, to refuse permission to aliens to enter British territory was contested by Sir W. Phillimore on behalf of the alien in 1891, in the case of Musgrove v. Chun Teeon Toy (L.R. 1891, A.C. 272), and the privy council said that the question involved such important considerations that they would express no opinion as to it, and would decide the case solely under the act of Parliament invoked by the Australian government. Lord Herschell intimated that no authority existed that an alien had a right of action for exclusion from the country.
As eminent an authority as Prof. Dicey makes the unqualified assertion in his book on ‘The Law of the Constitution‘ that—‘The crown cannot, except under statute, expel from England any alien whatever, even though he were a murderer, who, after slaughtering a whole family at Boulogne, had on the very day crossed red-handed to Dover. The Executive therefore must ask for, and always obtains, aid from Parliament.”