With this question
summarize the reason for writing the declaration of independence

The declaration of independence was written because the leaders of the thirteen colonies thought that they should give a formal explanation about the congress having voted in favor of the independence of the colonies.

Explanation:

On July 4, 1776, the Second Continental Congress held in Philadelphia, Pennsylvania, passed the Declaration of Independence. Its lead author, Thomas Jefferson, wrote the Declaration as a formal explanation of why Congress voted on July 2 to declare independence from Britain, more than a year after the start of the American Revolutionary War, and as a declaration announcing that the thirteen American Colonies were no longer part of the British Empire. Congress published the Declaration of Independence in several ways. It was initially published as a printed newspaper that was widely distributed and read to the public.

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