It seems likely that the oral argument before the U.S. Supreme Court on November 9 will interest immigration specialists but not the public at large. The issue—whether Congress can discriminate against U.S. citizen fathers in awarding citizenship to foreign-born children—is, for most people, pretty obscure.
But if the evening of November 8 has ended in a surprise, Lynch v. Morales-Santana may draw a lot of sudden attention. Observers will scan it closely for signs of the Court’s attitude toward President-elect Donald Trump’s plans to “shut down” Muslim immigration to the U.S.
That constitutional question has hovered uneasily in the background throughout the campaign. A “Muslim ban” would certainly be unwise and un-American. But would it be unconstitutional?
In any other area of government policy, the answer would be somewhere between “yes” and “hell, yes.” For the U.S. to discriminate so baldly by religion against anyone in the country—citizen or alien, documented or undocumented—would a gross violation of the principle of equal protection, which applies to the federal government by virtue of the Fifth Amendment.
But immigration law is, in many ways, a constitution-free zone, governed by what the Supreme Court has called “the plenary power of Congress” over decisions of who may enter the U.S. and who may not. The “plenary power doctrine” essentially holds that Congress can make distinctions among immigrants—including some based on sex, race, and national origin—that (as the Court said in 1976) “would be unacceptable if applied to citizens.” Thus, the Court’s approach to this issue might give a hint about how the justices would react to a statute—or a Trump executive decision––banning Muslim immigration to the U.S.