The Declaration of Independence is largely a bill of particulars citing specific instances of "repeated injuries and usurpations" on the part of the King of Great Britain. The Preamble, which you cited, is an effort to put those specific economic and political grievances into a philosophical framework -- moral cover, if you will, to justify the Revolution beyond merely a list of gripes.

The Declaration of Independence is a fine statement of the principles which led to the Revolution, but it has no force or effect of law. It is, in fact, in contravention of United States law, which prohibits insurrection, rebellion and seizure of Government property. Americans who presented such a declaration to the government today and acted on the same could be arrested and charged with treason. Interesting, isn't it?