Although it was before my time (and probably yours), you possibly may have read or heard, as I have, that this question was addressed about 140 years ago. I think generally it is referred to and written about, in the United States at least, as the Civil War.
Another clue might be that short statement referred to as the Pledge of Allegiance - cfr in relevant part..."one Nation, under God, indivisible..." There are more than a few court cases, I am advised, that address this issue, both directly and indirectly.
A more serious question is" What the hell is the AOC? Later.
I assume he means Articles of Confederation.
I believe that the one nation under God is a twentieth centry idea. The AOC is the Articles of Confereration.
I think he/she means Articles Of Confederation. The document under which the States united, more or less, mostly less, after the revolution and preceeded the Constitution.
I think the one country question is pretty well answered by the power to negotiate treaties being given to the President, with the advice and consent of the Senate.