It is likely that § 265 grants the Executive sweeping authority
to prohibit aliens from entering the United States during a
public-health emergency; that the Executive may expel aliens
who violate such a prohibition; and that under § 1231(b)(3)(A)
and the Convention Against Torture, the Executive cannot
expel aliens to countries where their “life or freedom would be
threatened” on account of their “race, religion, nationality,
membership in a particular social group, or political opinion”
or where they will likely face torture.