The Declaration of Independence declared the United Colonies to be "free and independent states," with the following context:
We, therefore, the representatives of the United States of America, in General Congress assembled, appealing to the Supreme Judge of the world for the rectitude of our intentions, do, in the name and by the authority of the good people of these colonies solemnly publish and declare, That these United Colonies are, and of right ought to be, FREE AND INDEPENDENT STATES; that they are absolved from all allegiance to the British crown and that all political connection between them and the state of Great Britain is, and ought to be, totally dissolved; and that, as free and independent states, they have full power to levy war, conclude peace, contract alliances, establish commerce, and do all other acts and things which independent states may of right do. And for the support of this declaration, with a firm reliance on the protection of Divine Providence, we mutually pledge to each other our lives, our fortunes, and our sacred honor.1
This was then retained in the Articles of Confederation:
To all to whom these Presents shall come, we the undersigned Delegates of the States affixed to our Names send greeting.
Articles of Confederation and perpetual Union between the states of New Hampshire, Massachusetts-bay Rhode Island and Providence Plantations, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, Virginia, North Carolina, South Carolina and Georgia.
I. The Stile of this Confederacy shall be "The United States of America".
II. Each state retains its sovereignty, freedom, and independence, and every power, jurisdiction, and right, which is not by this Confederation expressly delegated to the United States, in Congress assembled.2
And this was eventually ceded by Great Britain in 1783 by right of revolution, via the Treaty of Paris:
Article 1: His Brittanic Majesty acknowledges the said United States, viz., New Hampshire, Massachusetts Bay, Rhode Island and Providence Plantations, Connecticut, New York, New Jersey, Pennsylvania, Maryland, Virginia, North Carolina, South Carolina and Georgia, to be free sovereign and independent states, that he treats with them as such, and for himself, his heirs, and successors, relinquishes all claims to the government, propriety, and territorial rights of the same and every part thereof.3
However the federal government later claimed, that the states were not individually independent; but only that they were collectively independent as dependent states of a singular national union, which (allegedly) was the only state that won independence from Great Britain.
Accordingly, the federal government claims that the phrase "free, sovereign and independent states" does not mean what it seems: i.e. separate nation-states.
So what does it mean, according to the federal government? Lincoln claimed that:
"Therein the "United Colonies" were declared to be "free and independent States;" but even then the object plainly was not to declare their independence of one another or of the Union, but directly the contrary, as their mutual pledge and their mutual action before, at the time, and afterwards abundantly show.
This implies some declared dependence by the states upon each other and/or "the Union;" however the precise details are not given. The "mutual pledge," as shown above, was strictly personal among the representatives themselves; via with the words "We, therefore, the representatives of the United States of America, in General Congress assembled". They were not pledging on behalf of the united states themselves; not would this imply national dependence on any such "union."
Lincoln's continued list of claims, is likewise fraught with inaccuracy:
The express plighting of faith by each and all of the original thirteen in the Articles of Confederation, two years later, that the Union shall be perpetual is most conclusive. Having never been States, either in substance or in name, outside of the Union, whence this magical omnipotence of "State rights," asserting a claim of power to lawfully destroy the Union itself? Much is said about the "sovereignty" of the States, but the word even is not in the National Constitution, nor, as is believed, in any of the State constitutions. What is a "sovereignty" in the political sense of the term? Would it be far wrong to define it "a political community without a political superior"? Tested by this, no one of our States, except Texas, ever was a sovereignty; and even Texas gave up the character on coming into the Union, by which act she acknowledged the Constitution of the United States and the laws and treaties of the United States made in pursuance of the Constitution to be for her the supreme law of the land. The States have their status in the Union, and they have no other legal status. If they break from this, they can only do so against law and by revolution. The Union, and not themselves separately, procured their independence and their liberty. By conquest or purchase the Union gave each of them whatever of independence and liberty it has. The Union is older than any of the States, and, in fact, it created them as States. Originally some dependent colonies made the Union, and in turn the Union threw off their old dependence for them and made them States, such as they are. Not one of them ever had a State constitution independent of the Union. Of course it is not forgotten that all the new States framed their constitutions before they entered the Union, nevertheless dependent upon and preparatory to coming into the Union.
And of course the responses are plain: each state retained its freedom sovereignty and independence, their Union was purely international; the word "sovereignty" was expressly used in the Articles of Confederation and the Treaty of Paris; and each state was indeed "out of the Union" upon ratifying the Constitution to form a new, separate and more perfect union; which thus demonstrated that each state was indeed a sovereignty prior to doing so. Meanwhile Texas did not accede to the Union as a state, but strictly as US Territories, a portion o which were later awarded statehood, while the remaining territories contributed to the newer states.
So what could be the meaning of the phrase "free, sovereign and independent states;" if not separate nations; if this was described as having "the full power to levy war, conclude peace, contract alliances, establish commerce, and do all other acts and things which independent states may of right do."? And how?