The Declaration of Independence (U.S.A.) - Political II

[Samerron]

I would like to go into more details of the following paragraph from the Declaration...

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.

Okay, lets see... First clause, we have the Government, which has a destructive effect on a sub-set of its people.
Well, the sub-set of the country and its people have the right to:
1) Abolish the form of government applied to them i.e. to the sub-set.
2) Institute a new government forming principles & powers to affect their safety & happiness.

Now, before moving on, we need to clarify the key terms; principles, powers, safety and happiness, and understand what is meant by these terms.
What is your understanding of these key terms?

Another question, is what gives the right for the sub-set to abolish the form of government? If the people of the sub-set don't like the act of their government, they can try to change it or live with it. Why to form a new independence? Why don't they move to a new country or a new place?