There has never been an independent state called "America," or any variation of that name.
America is strictly the name of a continent; and the current union known as The United States of America, is simply a continental union of independent states; just as the European Union, was a union among the independent states of the continent of Europe...while the United Nations is a global union of independent states.
And the current American union was formed by the Constitution in 1788.
The independent states simply delegated powers to the union, in the manner of any such agreement among continuing independent states; just as they did under prior union they had formed under the Articles of Confederation, before they won their independence from Great Britain.
After that, they were independent states; which obviously, do not lose their sovereign independence to conjoin as larger independent states, simply by failing to expressly retain it in international compacts.
On the contrary, they must expressly manifest an intention to relinquish their independence to another state— whether joining to become part of an existing nation-state, or uniting to form a new independent nation- state; as noted in Blackstone’s influential Commentaries, that in the case of a nonconfederate, “incorporate union” such as the 1707 union of England and Scotland, no rescission option existed:
“The two contracting states are totally annihilated [qua sovereign states], without any power of revival; and a third arises from their conjunction, in which all the rights of sovereignty … must necessarily reside.”
However the precise wording in that 1707 document that united England and Scotland into the single nation of Great Britain, expressly manifested this intention. To wit:
That the two Kingdoms of Scotland and England, shall, upon the first Day of May next ensuing the Date hereof, and for ever after, be united into one Kingdom by the Name of Great-Britain, and that the Ensigns Armorial of the said united Kingdom, be such as her Majesty shall appoint; and the Crosses of St. Andrew and St. George be conjoined in such a manner as her Majesty shall think fit, and used in all Flags, Banners, Standards, and Ensigns, both at Sea and Land.
This is because such national union can only be expressly manifested by the nations themselves.
It can never be inferred by outside interpretation; for the obvious reason that independent states are their own final authority, and hence any outside inference would be inherently void.
And this new “one Kingdom by the name of Great Britain,” was the very state from which the Founders seceded; and therefore they would naturally be the first to know the difference between national vs. international compacts.
In contrast, neither the Constitution, or any other American founding document, ever likewise expressly manifests uniting the individual independent sovereign states together, to create a single new independent nation-state, to which they would become dependent states.
Rather, the Constitution is an international compact, just as with the UN or the EU, or indeed the Articles of Confederation.
The main difference is that it was established by the respective people of each independent state, who were thus established as the supreme final authority therein; and they simply delegate various powers to state and federal governments, as detailed in the body of the Constitution.
Therefore the collective franchise-holding citizens of each state, are the national parties to the international constitution; and as James Madison explained in his 1800 Report on the Virginia Resolutions; “it follows of necessity that there can be no tribunal, above their authority, to decide, in the last resort, whether the compact made by them be violated; and consequently, that, as the parties to it, they must themselves decide, in the last resort, such questions as may be of sufficient magnitude to require their interposition.”