I'm NOT a lawyer; I'm just trying to get a BASIC IDEA about this subject matter.
NOTE the source in this (2014) link; it starts with some international concepts.
- ".. aliens, on the other hand, (were) defined more in terms of obligations between the state and the alien’s home state.."
- ".. stateless individuals were essentially at the mercy of all states in whose territories they might find themselves.."
- "(Aliens) continued to owe allegiance to (their) native state, aliens in the territory of a host state owed “local allegiance”.. for the temporary protection of the laws of the land."
enjoy all of the privileges of citizens, such as the right to participate in
THE MELDING OF ".. international law concepts into (US) domestic law.." follows:
* COMMENT: Wiki indicates FOUR acts "signed into law by President John Adams in 1798"
 The NATURALIZATION ACT "made it harder for an immigrant to become a citizen"
 ALIEN FRIENDS ACT "allowed the president to imprison and deport non-citizens who were deemed dangerous"; expired 1801
[3} ALIEN ENEMY ACT for aliens "who were from a hostile nation"
"That 'persons' under the Fifth Amendment.. includes citizens and aliens within the United States is well settled"
There is more:
"Zadvydas v. Davis, ..
the United States, including aliens, whether their presence here is lawful, unlawful, temporary, or permanent.”
"Aliens who have not acquired any domicile or residence in the United
States are generally entitled to very little process to determine whether they
should be permitted to enter the country".
"Although covered by the Due Process Clause, an alien seeking entry at a port of arrival is not constitutionally entitled to a judicial hearing, even if claiming to be a U.S. citizen"
'deportable', compared to 'excludable' aliens, for purposes of removal
hearings, has thus traditionally been stark."
"Deportable aliens are those who have entered the country but have become ineligible to remain."
"Deportable" (VISA overstay)
"Inadmissible" (Illegal Entry)
- "The law of war permits the internment of enemy civilians and combatants and the confiscation of their property, regardless of whether the alien demonstrated any actual hostility."
- ".. enemy aliens present in the United States may be interned.. or
deprived of property by summary administrative proceeding."
without the ordinary due process accorded to noncitizens in deportation
proceedings in the United States, even after hostilities have ended."
States eliminates due process rights of any enemy fighter, whether a foreign
invader or a citizen who has taken up arms against the government during a serious rebellion."
- "339 U.S. 763, 782 (1950) (rejecting the contention that nonresident enemy aliens engaged in hostilities against the United States were “persons” within the meaning of the Fifth Amendment and had the right to access the courts to petition for a writ of habeas corpus)."
enemy combatants (who are not technically enemy aliens) detained by the
United States in an area subject to its jurisdiction overseas."
Enemy Alien (legal, deportable or excludable/inadmissible Enemy IN THE US)
Enemy Combatant (Alien or US Enemy DETAINED IN A US OVERSEAS AREA)
NOT looked into (in this thread) is any EXTRATERRITORIAL APPLICATION OF THE DUE PROCESS CLAUSE or US CRIMINAL LAW for citizens or aliens abroad.