A lawyer and political activist prior to the revolution , Adams was devoted to the right to counsel and presumption of innocence . He defied anti-British sentiment and successfully defended British soldiers against murder charges arising from the Boston Massacre . Adams was a Massachusetts delegate to the Continental Congress and became a principal leader of the Revolution . He assisted in drafting the Declaration of Independence in 1776 and was its foremost advocate in Congress . As a diplomat in Europe , he helped negotiate the peace treaty with Great Britain and secured vital governmental loans . Adams was the primary author of the Massachusetts Constitution in 1780 , which influenced the United States ' own constitution , as did his earlier '' Thoughts on Government ''
Boston Massacre
Boston Massacre
John Adams