Of course military dependancy is important, but you will find many on this site who follow your initial rationale to extremes and argue that there should be no standing army.
Seriously.
They read the Constitution in such a narrow way that when it says that Congress shall not budget for the military in no more than 2 year blocks that means that the Founders never intended the Federal Government to have a standing army, just that the Congress could raise an Army and support it for 2 years at a time.
That is the level of discussion that I must deal with each time I come into a discussion of Governmental spending. Frustrating, right?
The fact is that as a precept in the Declaration of Independance, Jefferson was making clear that Government should be something that is beholden to the constituency and not the other way around. He was saying that Government should support a people and provide them freedom rather than a people provide Government with largesse. He did not mean, and neither did Locke or Paine, that Government's only function was to directly support individual rights. It is a function of Government, but as you point out providing for common defense, organizing itself to be effective, and supporting the advancement of it's people as a whole are also functions of a Government.
Sometimes that means that the Government does things that are unpopular to a large minority of people. Sometimes that means that the Government does things that are unpopular to a majority of people. Does that mean that the Government does not have the right to do them? If the people gave the Government that right, you better believe it does.
Emminant Domain.
Does the Government have the right of Emminant Domain? The writer of the Declaration of Independance believed so and was very convinced of that right of the Federal Government after the Louisiana Purchase. How does that square with your beliefs? How can the concept of Emminant Domain be reconciled with Government's only duty being to uphold individual rights? How could Jefferson write the Declaration of Independance and yet support such a notion?
The same way he could write "All men are created equal" and still own slaves. Idealism and Pragmatism must both be employed in Governance, for a Government of one without the other is doomed from the start.
The fact is that as a precept in the Declaration of Independance, Jefferson was making clear that Government should be something that is beholden to the constituency and not the other way around. He was saying that Government should support a people and provide them freedom rather than a people provide Government with largesse. He did not mean, and neither did Locke or Paine, that Government's only function was to directly support individual rights. It is a function of Government, but as you point out providing for common defense, organizing itself to be effective, and supporting the advancement of it's people as a whole are also functions of a Government.
We may, to some extent be arguing semantics at this point, but I'm not sure of that. I agree that Jefferson was making the point that government existed for the individual citizens and not the other way around which is how "subjects" were more or less treated in monarchial structures.
On the other hand, and without the exact wording of the Declaration in front of me, my recollection is Jefferson's were pretty much 1) individuals have rights, 2) governments are instituted to secure those rights, and 3) government derives its just powers from the consent of the governed. Governments are instituted to secure rights. Jefferson spoke of no other purpose for government. None. That he purchases Lousiana requires, in my mind anyway, that he link that purchase somehow to the securing of one or more rights. Perhaps he linked it to the protection of the nation, surely an action designed to secure rights of life, liberty, and property.
One point I want to make is that government is not all powerful and I got the impression from one of your earlier posts that you pretty much thought local government had most any power not prohibited it by the Constitution. Thus my disagreement. Government power must both be given it by consent of the governed and used solely to secure rights. You or I may not agree with the rationale government uses to link a law to a right but that's a different matter.
I need a little more time to read the rest of you post, so hope to comment more later.