If a naion has a right to establish a governmet or change it then the existance of a nation does not depend on the existance of its government .
Government on the other hand , existing with a nation is possible and without is not.
Yes, and?
I should, I suppose, take a moment to say that a key factor you're still missing is that if the government exists at the will of the nation, or as the Declaration says, the people, then the government represents the will of the people (or at least a majority of them), or in your terminology, the nation. This is especially so in a democratic republic as we have in America. Thus your attempt to completely separate the nation from the government is fundamentally flawed.
You will have to point out what the flaw is .
If I can't make a distinction between an apple and an apple tree , if I can't make a distinction between a car and an asdsembly line , if I can't make a distinction between a product and its producer then I can't make a distinction between a government and its people.
I am sure that King George III would consider this to be wrong , he himself was England , but the Attitude that the Government is for the people and not that the people are for the government is more in line with the sprit of '76, more like what I agree with.
I might be misunderstandig you , but you seem to be claiming that gobvernment and nationhood are inseprable , if so I could certainly point out several instances of governmental change that did not change the nation or people.