Final answer:
The grievances in the Declaration of Independence were designed to justify American independence by cataloging King George III's oppressive policies and highlighting the colonists' unrepresented legislative interests and principles of self-government.
Step-by-step explanation:
The list of grievances in the Declaration of Independence primarily serves the purpose of justifying the American colonies' separation from Britain, providing a catalog of complaints directed at King George III's oppressive rule. This list underscores the refusal of the colonists to tolerate any longer the king's infringement upon their economic interests and principles of self-government. Highlighting the absence of representation in legislative decisions, the maintenance of a standing army during peacetime, the quartering of troops without consent, and the evasion of proper legal trial for royal officials, the Declaration of Independence stands as a compelling indictment of the British government's policies.