Interesting, thanks for that. After reading a bit more, it seems, rather than "threat to national security" as claimed by NPR, Trump is more likely using "threat to U.S. foreign policy interests" as defined in Section 237(a)(4)(C) of the Immigration and Nationality Act (INA), which became law as part of the Illegal Immigration Reform and Immigrant Responsibility Act of 1996 (IIRIRA) signed by Bill Clinton. Perhaps that law needs to go.
>Section 237(a)(4)(C) of the Immigration and Nationality Act (INA)
>An alien whose presence or activities in the United States the Secretary of State has reasonable ground to believe would have potentially serious adverse foreign policy consequences for the United States is deportable.[0]
What one deems reasonable ground can speak very clearly about their intended application of that law.
My understanding from my law training is that, perhaps surprisingly, "reasonable" is an objective, not subjective standard. The "reasonable" standard asks whether a hypothetical, ordinary and rational person, acting reasonably, would reach the same conclusion based on the same information. And this can be decided by a judge or jury if/when necessary.
> The "reasonable" standard asks whether a hypothetical, ordinary and rational person, acting reasonably, would reach the same conclusion based on the same information. And this can be decided by a judge or jury if/when necessary.
It's subjective in other words. A jury would be unnecessary otherwise.