Why is the Declaration of Independence important to American history?
Most people view the Declaration of Independence as simply an announcement, but it's quite a bit more than that. It was written mostly by Thomas Jefferson as a list of charges against King George III and the British Empire and explains in detail why it was that the colonies were breaking away from the mother country.
Regular elections, limits on police and government powers, freedom of speech and jury trials are all part of our Constitution now, but the ideas to include those values started with what the British had done to the colonists over the years, and what they wanted to protect themselves from enduring ever again. The Declaration is a summary of those ideas and a guideline the Founding Fathers would use later.