The notion that Constitutional protections cannot apply to non-citizens is simply not true, even when applied to non-citizens being held by the US off of US soil.

My point is that those are different outcomes, not the same; one protects me - a person in the US who is not a US citizen - and the other does not. The difference is also a furtherance of a generally authoritarian idea that non-US-citizens should have not equal protection under the law.

No, the argument was that foreign terrorists and other non-state enemy combatants were not "subject to the jurisdiction" of the US legal system (because they weren't on US soil when captured, and as non-state combatants that weren't covered by any treaties to which the US was a party) and thus also not afforded its protections. However, as a matter of international law, a country generally has legal jurisdiction over any person physically present in the country, whether present legally or otherwise, excepting specific diplomatic personnel (as defined by local law or treaty).

This was the reason for holding them indefinitely in an military facility located in another country. However, under US law, military facilities are considered US soil, and so persons being held in US military facilities are subject to the jurisdiction (and protection) of the US legal system.

This reminds me a bit of the Roman concept of the pomerium. Anything outside of the arbitrary line deciding what was Rome and what wasn't, was "anything goes."

In the SCOTUS rulings on Guantanamo, SCOTUS went further and stated that they would have ruled the same way if it had been a CIA facility instead of a military facility, so long as Cuba had granted the CIA permission to exclusively use the land for its own purposes.

The 14th amendment was ratified in 1868. The total population of the US in 1870 was around 38 million. The total number of immigrants was around 2 million. The slave population was around 5 million.

The implications of the 14th amendment are clear today and they may even have been clear then. Nevertheless the most pressing, most politically salient issue was the newly freed slaves. In one day (the day after ratification) the United stares gained 5 million new citizens.

I would not be surprised at all if the people involved at what time were a tad bit myopic, with respect to the problem at hand.

EDIT: In fact in 1860, the us census measured 4.1 million people not born in the United States. Is your claim honestly that while the census actively measured this, not a single person realized what birthright citizenship would mean for the children of those 4.1 million non-natives?

I really hate that usage of the word.

I mean, your basic argument is that Thomas is just pointlessly making semantic disagreements with the majority that would have no effect on this or any other conceivable case because either basis for incorporation produces exactly the same result not only on the present case but all possible cases. While I have a low opinion of Thomas, it's not quite that low.

Cannot they already do this to some limited extent (and perhaps are even required to do so)? For example, laws concerning voting.

Others are only for citizens (and EU citizens, but via a strange legal method), but the most fundamental ones state "Everyone", not "every citizen".

Smart move. :-)

Not having basic protections for non-citizens would be rather worrying, but let's not act like the mere existence of a difference is worth freaking out about.

EDIT: To be clear, I'm not suggesting that Justice Thomas's concurrence not providing these protections to non-citizens would be a good thing. I'm just saying that 'non-citizens should have the same rights as citizens' isn't a position held by any country on the planet.

In my opinion, not having your property taken unfairly by the police is more of a basic right everyone should enjoy, rather than a special right afforded to citizens like voting.

That's fine, but affording no rights to non-citizens would be highly problematic. Some argue the Constitution doesn't protect the rights of illegal immigrants, for example, but it makes clear distinctions by using "persons" in some spots and "citizens" in others.

Persons have a right to due process. Citizens have a right to vote. The difference is very important.

The average ruling in a single minor case today is longer than the entire Constitution.

Which is why we have the status quo: the vast majority of rights enjoyed my U.S. citizens and residents are enjoyed by aliens, with some discretion.

"... The panel affirmed a conviction for possessing a firearm while being an alien unlawfully in the United States in violation of 18 U.S.C. § 922(g)(5)(A)."

http://cdn.ca9.uscourts.gov/datastore/opinions/2019/01/08/15...