Harvard Law School Professor Cass Sunstein wrote in a Bloomberg opinion piece last week that courts are not likely to rule that the national emergency is unlawful, even if Trump’s own statements and actions, as well as facts, do not support his declaration.

That’s because under the National Emergencies Act of 1976, Congress gave the president broad power to determine what constitutes a national emergency.

“It’s an emergency under federal law because Trump said it is,” said Jonathan Turley, a George Washington University professor of law and contributor to The Hill. “The National Emergencies Act has one conspicuous omission: It doesn’t define what an emergency is.”

And since Congress gave itself the power to overturn a declaration — by passing a resolution with a simple majority that would require a two-thirds majority to override a veto — the courts may decide the dispute is not for them to decide.