Legal scholars have been divided for months about whether Trump’s proposals would hold under the constitution. Congress and the White House share authority to decide eligibility for citizenship and entry into the country, and the supreme court has never directly confronted whether religion could stand as a valid reason to exclude some people over others. Trump’s orders do not explicitly name Islam but clearly target Muslim-majority countries, meaning it could test the constitution’s guarantees of religion and due process, as well as the president’s authority over immigration in general.
In the 1890s, the court upheld a ban on Chinese immigrants, but those cases were about race – and the arguments behind them have been abandoned. In 1972, the court ruled 6-3 that the White House could bar a Marxist Belgian from entering the US, deferring to the president’s discretion. That case has convinced some legal experts that the court would uphold the new orders, but Trump has repeatedly characterized his plans in sweeping terms: an entire class of people, rather than a single person, and an explicit preference for one religious group over another. And his intent could have bearing on a court’s assessment of the law.
In the 1972 case, Kleindienst v Mandel, the court kept the door open to future challenges, saying the White House needed reasons that were “facially legitimate and bona fide”. The American Civil Liberties Union has already promised to challenge Trump’s orders: if they can summon the allies and standing for a case, Trump would have to prove in court that he has legitimate reasons for such a sweeping rule. The Council on American-Islamic Relations has already announced it intends to sue, alleging an improper “religious motive”.