The Continental Congress

Twelve of the 13 colonies sent representatives to the First Continental Congress, which met in Philadelphia in September 1774. At that meeting, resolutions and a statement of rights and principles were adopted that still looked to a peaceful settlement with Great Britain. The Second Continental Congress convened in May 1775, after the battles of Lexington and Concord. Without legal authority to do so, the Second Continental Congress assumed governmental functions. It established a postal system, created a navy and marine corps, negotiated treaties with the Native Americans, and looked for allies overseas. Most important, the Congress formally voted to declare independence from Great Britain. 

The Declaration of Independence

Written chiefly by Thomas Jefferson, the Declaration of Independence (adopted July 4, 1776, by the Second Continental Congress) provided the specific reasons for the break with Great Britain. Its philosophical justification drew heavily from John Locke's Two Treatises of Government (1690). Locke argued that people have natural rights — "Life, Liberty, and the pursuit of Happiness," in Jefferson's words — that cannot be taken away. Governments, which get their power from the consent of the governed, are created to protect these rights. When a government fails to do so, the people have a right to abolish it and create a new form of government. 

State constitutions

The idea that the people were the source of power was also included in many of the new state constitutions. Having just rebelled against the king, most states severely limited executive power. The legislatures were supreme, and in many instances not only made the laws but also appointed the governors, judges, and other officials. Individual liberties were usually safeguarded. The state legislatures continued to enjoy considerable authority under the Articles of Confederation.