Final answer:
John Adams used legal and moral appeals in his correspondence with fellow colonists, advocating for justice and representation based on British law and the right to fair trial, even for his adversaries.
Step-by-step explanation:
John Adams, in his communications and actions, appealed to the legal and moral principles of justice and representation, underscoring the importance of legal fairness and adherence to the rule of law. These appeals were evident when he took on the defense of the British soldiers involved in the Boston Massacre, despite his personal advocacy for colonial rights. Adams believed that even those accused of crimes against the colonists deserved a fair trial, reflecting his commitment to the principles of justice. This stance was an appeal to the law of the land and the colonists' entitlements under British law, specifically the 1689 Bill of Rights and Act of Religious Toleration. He consistently expressed the colonists' grievances with the lack of representation, which led to repeated petitions for redress of grievances, and although he did not expect redress but 'increased resentment and double vengeance', his belief in legal channels was unwavering.