Does the POTUS have the authority to surrender the US to a foreign nation?

Yes current events and all, but just a GQ, does the President have that authority, and if not who?

It’s a meaningless question unless you define “surrender” more precisely.

Any surrender would ultimately have to be made official by a treaty and the Senate has the final word of whether or not a treaty is ratified.

But the President is Commander-in-Chief of the armed forces. He could give orders to the armed forces telling them to surrender to another country. At that point, the other country would have won a de facto victory and any attempt by the Senate to refuse to acknowledge this with a de jure treaty would be meaningless.

Give up sovereignty of the US to a foreign power upon request, demand, tribute or even gift?

The plain definition of “giving up sovereignty” would be to invest decision-making powers in a foreign body, which would be contrary to the enumerated powers of each branch of government under the Constitution. So if the President attempted to assert that the laws passed by the parliament of a different country actually constituted U.S. law, that would be directly contrary to Art I sec 1 which directs that all legislative powers are invested in the U.S. Congress.

However, Art II also provides that the President has pretty broad powers in foreign relations. Simply agreeing, or even promoting the interests of, countries that some consider hostile carries political risks, but isn’t directly illegal. Those are policy matters that are, in general, political questions subject to the checks and balances created by the separation of powers between the Executive Branch and Congress.

But since you mention gifts, it is generally illegal for U.S. officials to receive compensation from foreign sources. (This is actually a matter of controversy regarding Trump’s pre-existing business relationships; but a President directly receiving cash from a foreign government as a bribe is unquestionably illegal.)

I am talking about the POTUS gifting US sovereignty to a foreign power, I’m not talking about the POTUS receiving gifts. Though gifting the US is asked just to see how far it can go, the other options (meaning demand or request by a foreign nation to surrender or surrender as tribute to them) were more to my question.

Perhaps we have a language barrier. It seemed from your question that a foreign power made a request or demand, sought tribute, or provided a gift, in order to get the President to do something. I see now that you meant that the President was “offering” sovereignty, that’s fine.

But the terminology of the question is still odd. Sovereignty is a concept (though an important one). Powers are what the government exercises to make policy. To the extent that a President (or Congress) seeks to give constitutional powers to someone else, the Constitution forbids that.

To the extent that the President (or Congress) seeks to exercise lawful power in a manner that is unseemly in the amount of deference given to another country, with the exception of things like treason and espionage (both of which have specific definitions), for the most part there’s nothing legally wrong with making bad policies.

To put it another way, treaties are a very well established way of sharing U.S. sovereignty on certain matters: for example, the U.S. has signed treaties limiting the number of nuclear weapons we can possess. A sovereign nation can determine how many nukes they want; but coming to a legal agreement to limit them, in spite of the legal ability to do whatever we want, is a form of sharing sovereignty with another nation. And of course, there are checks and balances built into that power, but critics could say that any treaty signs away U.S. sovereignty to some degree or another – which is kind of true in a specific context.

Maybe if you want a more specific answer, you could pose a more specific question.

No, or at the very least not without congressional assent.

Doesn’t matter if the POTUS does as the “others” still have to make good on enforcing their control. One can claim any land or other material they want but they still have to be able to hold it against all others. A sizable portion of well over 350 million people will have to agree with the decision for it to have any affect.

The story goes that when President Minh attempted to surrender in 1975, he was told something like, “you cannot give up what you do not have.”

Shit, I’ve just been reading Shakespeare’s Henry VI. All three parts. [Aside]: Anyone wants to know if the Bard is still relevant, I’m reading nothing but the words of Trump, McConnell, Paul and assembled worthies throughout this epic. [/aside]. POTUS is not a king. America is not his to gift. Search for some of the many threads on Are we a republic or democracy? Short answer, we’re both. But the whole Republic part keeps the POTUS from having anywhere near that discretion to give away our sovereignty. It doesn’t belong to him.