The Constitution of the United States.

The United States Constitution is a system of basic laws and principles; it defines the rights of American citizens and sets limits on what the government can and cannot do within its power. It provides the framework for the federal government and establishes a system of federalism, by which responsibilities are divided between the national government and the states' governments. One of the important principles on which the Constitution is based is the separation of powers, which divides power between the three separate branches of the federal government. The legislative branch (Congress) has the power to create laws; the executive branch (represented by the president and advisers) has the power to enforce laws; and the judicial branch (represented by the Supreme Court and other federal courts) has the power to dismiss or reverse laws that it deduces are "unconstitutional."
In 1781, the United States won its independence from England. A majority of Americans felt a stronger obedience to their individual states than to their new country. Most people did not wish to create a strong central government, far away from their homes, from which they felt they would have little or no command; they had just fought a long and bitter war to free themselves from such government. In response to these impressions, leaders assembled the new American administration according to a document known as the Articles of Confederation. The Articles gave each state a great deal of independence and depicted little more than a fellowship of friendship between them. It became obvious that the Articles of Confederation would not be sufficient to hold the nation together; therefore the Constitution was created.
The Constitution of the United States reflects the colonial and revolutionary experiences of early Americans. Freedom from abusive government was a reason for the colonies' revolt against British rule, while English tradition also provided ideas about government, power, and freedom...