Can A U.S. State Ban One Or More Specific Foreigners

To be blunt, I call BS on that unless a reliable cite is provided. Under the Vienna Convention on Diplomatic Relations, which is the binding international treaty that governs the work of embassies (and to which the US is a party), the host state must allow embassy staff freedom of travel across its territory. This is not without exceptions; the host state can restrict access to zones “entry into which is prohibited or regulated for reasons of national security”. But I’d argue that this only applies if entry into the zone is restricted to the general public as well; targeted access restrictions for foreigners to areas that any domestic citizen can freely travel to would not seem to fall under this exception.

Would you consider the Library of Congress a reputable site?

But did this apply to Soviet diplomats accredited to the US?

There is this, from the article:

“In 1962, the Kennedy administration lifted travel restrictions for ordinary Soviet citizens. However, Soviet reporters and government officials were closely monitored, and the U.S. government limited where they could visit until the end of the Cold War.”

To be fair, I’m not sure this answers the specific question. But it certainly doesn’t say there were any exceptions for diplomats.

I’ll partially retract my previous statement; according to this DoS page, the restrictions were, from 1955 to 1962, applied to all Soviet citizens, including diplomats, except those posted to the United Nations in New York.

I am afraid not. It was described to me in a meeting by an FBI agent back in the early 90s. He was talking about events back in the 70s and 80s.

didn’t the Suprem Court just ruled Texas arresting illegals was ok for now?

De jure or de facto? I believe they declined to overrule some sort of administrative ruling from an appeals court and due to tradition they never overrule that specific type of ruling. Does someone have the details?

The Supreme Court declined to review the Fifth Circuit’s denial of a stay. Appellate courts normally enter such stays automatically but the Fifth is unusual. The SCOTUS order doesn’t address the merits of the case which is being heard by the Fifth next month.