Those 'states' were not part and British Union. They were colonies. They had no representatives in London. They had absolutely no say in the policies of Parliament or the British Crown. Their complaints to the British Union were ignored. Their pleadings for just treatment were ignored. Read the Declaration... they listed their reasons and justifications, in detail.
It was not 'secession.' It was a Revolution against 'intolerable oppression.'
No comparison to what happened in 1860-61.
That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, --That whenever any Form of Government becomes destructive of these ends, 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.
Sounds as though the Declaration of independence says that people have a right to secede.
It was not 'secession.' It was a Revolution against 'intolerable oppression.'
Well if it was "intolerable oppression", why didn't Canada secede too? Apparently they thought it was tolerable. In any case, you are quibbling over word definitions. You want to call it "Revolution" which it was not. The same people were in Charge after the war as were in charge before the war, hence it was *NOT* a revolution it was a war for Independence, which is pretty much the same thing as "secession".
A Revolution is where people who were not in power take over power from people who WERE in power. Our leadership remained pretty much the same before and after the "revolution" so it does not accurately fit the definition of a revolution. The "have nots" did not chase out the "haves", the "haves" were in power before, and the "haves" were in power after.
I will point out that we call it "Independence day", not "Revolution day."