The Supreme Court upheld President Trump’s travel ban in a 5–4 decision. The travel ban undermines a core principle of the U.S. immigration system since 1965: that the law will not discriminate against immigrants based on nationality or place of birth. The president has rewritten our immigration laws as he sees fit based on the thinnest national security pretext, setting a dangerous precedent for the future.

The ban entirely lacks any reasonable basis in the facts. Nationals of the targeted countries have not carried out any deadly terrorist attacks in the United States, and they are also much less likely to commit other crimes in the United States. Nor are their governments less able or willing than others to share information or adopt certain identity management protocols.

We now know that the report that supposedly provided the detailed, “extensive,” and “thorough” analysis of every country in the world was just 17 pages, giving barely a tenth of a page to summarize facts relating to 200 countries. It was great to see Justice Sotomayor raise this fact in her dissent (p. 19), possibly as a result of a letter that Cato adjunct Ilya Somin sent to the court summarizing a post that I wrote on the subject.

As a matter of policy, no president should be given such broad power to determine immigration law. While the travel ban currently affects only a small share of immigrants and foreign travelers, all legal immigrants should be concerned that the president will wield this power against them next. Congress should immediately intervene to preserve its power to determine immigration policy.