To date, every court to have considered Trump’s executive order banning birth right citizenship, issued on day one of his administration, has blocked it. But he has doggedly persisted in his contention that birthright citizenship is unconstitutional, an idea widely considered a fringe view because the Supreme Court ruled to the contrary 127 years ago, and that decision has never been disturbed.

A group of states challenged Trump’s order, contending that the right to birthright citizenship is not, even remotely, an open question. As they put it in their Supreme Court brief: “For over a century, it has been the settled view of this court, Congress, the Executive Branch, and legal scholars that the Fourteenth Amendment Citizenship clause guarantees citizenship to babies born in the United States, regardless of their parents’ citizenship, allegiance, domicile, immigration status or nationality.”