I'm aware of what the law is, but this isn't really responsive to my argument. I'm arguing from principles, not existing law.
Why shouldn't the same principles we apply to our own people apply to foreign people? Isn't freedom of speech a universal principle? If not, what makes outsiders' speech substantively different from ours that we should censor it?
Moreover, people in the U.S. are free to say the exact same things that foreigners might say. Why does it matter that it's coming from outside the country as opposed to inside it?
> Supreme Court precedent heavily uses phrases like ‘the constitution is not a death pact’
1/It was "suicide pact." 2/That was dicta from Justice Jackson in a dissent in Terminiello v. City of Chicago, 337 U.S. 1 (1949), not law.
> and ‘yelling fire in a crowded theatre is not protected speech’.
That was from an early free speech case in 1919 (Schenck v. U.S.) when speech restrictions were more broadly upheld--and it was not the question in the case (it was just an example). Freedom of speech has been significantly liberalized since then. Brandenburg v. Ohio, 395 U.S. 444 (1969) overruled Schenck: "[T]he constitutional guarantees of free speech and free press do not permit a State to forbid or proscribe advocacy of the use of force or of law violation except where such advocacy is directed to inciting or producing imminent lawless action and is likely to incite or produce such action."
> Unregistered foreign agents tend to be locked up, deported, or hung.
It sounds to me like you're just an unapologetic xenophobe.