Inseparable only applies so long as the ties that bind you are stronger than those that separate you. Once those ties are loosened through diverging philosophies then the ties are no more than chains used by one side to imprison the other. The ties that bound the divergent factions of the the Founders of our nation was the profound and unshakable belief in the liberty of men and that this liberty was not inferred on them by governments but was in fact the natural order of the universe. Two of our founders whom held the most divergent views on the role of the "national" government in public life were Alexander Hamilton and Thomas Jefferson but on the first principle of our founding they agreed;
The fundamental source of all your errors, sophisms, and false reasonings, is a total ignorance of the natural rights of mankind. Were you once to become acquainted with these, you could never entertain a thought, that all men are not, by nature, entitled to a parity of privileges. You would be convinced, that natural liberty is a gift of the beneficent Creator, to the whole human race; and that civil liberty is founded in that; and cannot be wrested from any people, without the most manifest violation of justice. Civil liberty is only natural liberty, modified and secured by the sanctions of civil society. It is not a thing, in its own nature, precarious and dependent on human will and caprice; but it is conformable to the constitution of man, as well as necessary to the well-being of society.
-Alexander Hamilton 1775
"The God who gave us life, gave us liberty at the same time."
-Thomas Jefferson 1774
So what actually tied these various slightly differing governing philosophies together was an overriding singular belief in the inherent liberty of man. But a mechanism needed to be found to not only explain this overriding principle of man's liberty but to establish the governing principles to protect them. Thus the Constitution, which while not perfect left open the pathway to amending to correct and to adapt to changing times. But most important of all it established a governing structure which was intended to protect the liberties of man which was the "tie that bound" us together and tied the Founders together..
Today it is again sophistry of the highest degree to claim that you can ignore this most basic of all ties, personal liberty, for the sake of some sort of communal governance. When the twentieth century progressive movement began to describe these protected rights as negative liberties "what government could not do to you, rather than what government could do for you" they unbound the ties which bind us. Because as an objective view of 20th century American history clearly shows we are "progressing" away from man's inalienable rights towards government's power to impose. This imposition of government power on the citizen is a fundamental principle of Progressive political ideology.
Because government does what all governments do as they grow, while claiming to do "for" the people they are in fact doing "to" the people. And what they are doing "to" the people is imposing on them laws and regulations that increasingly imprison them to the dictates of a less and less responsive government. This is why a growing Federal Government fits right into the progressive philosophy and is contrary to our Founder's philosophy.
We are less and less a representative democracy and more and more a fascist state, where connections and influence to the governing elite and its bloated bureaucratic institutions is what determines the" public " policy. Rather than WE THE PEOPLE which are supposed to be the beneficiary of and the rulers of the governing structure, the governing structure instead rules the people, "as government grows, liberty shrinks."
Those "special interest" connections are only possible because the Federal Government controls and influences more and more of public life and in a centralized location. If you want to influence policy for your own interest, go to Washington. This is why the DC area is now the richest region in the nation, it is where the money and the power is. We have gone from a nation where merit and industry is the backbone of our existence to one where political influence determines destiny.
To say that this has happened or is happening for the "public good" is naivety of the highest order. To say that the progressive philosophy is not primarily responsible for this is simply willful ignorance. But to say that this philosophical divergence from our founding principles is somehow an American principle is to stick a knife in our Founders and Framers back.
Progressivism was never intended to progress the ideals of democracy as envisioned by our Founders, but rather from its founding was intended to progress us away from our founding principles towards a more "enlightened" Utopian vision, based more on Marxism. To show how far removed Progressive thought is from founding principles it is only neccessary to quote their founding icons.
One of Progressive's founding members considered to be one of its great thinkers, the educator John Dewey who said:
"Natural rights and natural liberties exist only in the kingdom of mythological social zoology."What would Hamilton and Jefferson think of that? Is that a philosophy that binds us to our founding principles?
Then there is another leader of the early progressive movement Margaret Sanger the founder of the cherished progressive institution Planned Parenthood:
[We should] apply a stern and rigid policy of sterilization and segregation to that grade of population whose progeny is tainted, or whose inheritance is such that objectionable traits may be transmitted to offspring.
That just shouts, life, liberty and the pursuit of happiness doesn't it? As does this from Ms Sanger's "Plan for Peace":
Article 1. The purpose of the American Baby Code shall be to provide for a better distribution of babies… and to protect society against the propagation and increase of the unfit.
Article 4. No woman shall have the legal right to bear a child, and no man shall have the right to become a father, without a permit…
Article 6. No permit for parenthood shall be valid for more than one birth.
A fundamental tenant of progressive ideology IS that the American principle of individual liberty is flawed at its core.
Perhaps nobody consistently made this point clearer than the 26th President of the United States Woodrow Wilson an avowed progressive who said of the Declaration of Independence
“the rhetorical introduction of the Declaration of Independence is the least part of it…. If you want to understand the real Declaration of Independence, do not repeat the preface.”
“the rhetorical introduction" of course is all that meaningless verbiage about holding truths to be self evident, men are created equal endowed by their Creator with rights..blah, blah, blah. Wilson argued that this was just so much nonsense.
So when the progressive left or right for that matter tries to claim that they are part of the American fabric, they are right in one sense. They are the loose thread which is attempting to pull apart the fabric of the American union. Because if that union is not built on the founding principle of individual liberty there really is no union at all.
Are we indivisible? No we are very much divided not by the people who believe in our founding principle but by those who through sophistry attempt to destroy it. Because if you do not believe in individual liberty, you really don't believe in America at all.