"We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable rights, that among these are life, liberty and the pursuit of happiness. That to secure these rights, governments are instituted among men..."
Or, to use Frederick Douglass' nautical analogy, it is what keeps the pilot of the ship connected with the mast in the inevitable storms:
From the round top of your ship of state, dark and threatening clouds may be seen. Heavy billows, like mountains in the distance, disclose to the leeward huge forms of flinty rocks! That bolt drawn, that chain, broken, and all is lost. Cling to this day-cling to it, and to its principles, with the grasp of a storm-tossed mariner to a spar at midnight.""I have said that the Declaration of Independence is the RINGBOLT to the chain of your nation's destiny; so, indeed, I regard it. The principles contained in that instrument are saving principles. Stand by those principles, be true to them on all occasions, in. all places, against all foes, and at whatever cost.
But that's not what I meant by "practical".
"We hold these truths &c" gives a justification for forming a government, but doesn't specify what form of government should be established.
A good monarchy is as capable of securing the three "inalienable rights" as a good republic. A bad republic is as capable of infringing those rights as a bad monarchy.
"That to secure these rights, governments are instituted among men, deriving their just powers from the consent of the governed. "
That's commonly understood in America to refer to a democratically elected Republic ... but it could also refer to a popularly acclaimed king.
"That whenever any form of government becomes destructive to these ends, "
I'll just let that thought hang in the air for a moment ...
"it is the right of the people to alter or to abolish it, and to institute new government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their safety and happiness."
And that is really all it says about forming a new government. Nice ... but how do you form a government based on that?
The authors of the Articles of Confederation, and later of the Constitution both attempted to answer my question.
History will judge the efficacy of their efforts.