The United States was officially founded on July 4, 1776, when the Declaration of Independence was approved by 12 of the original colonies. Though the Declaration was not a formal governing document, it did announce that the states had united into their own nation.
The subsequent Articles of Confederation, a governing document that gave minimal power to a central government, was adequate for guiding the new nation through its war of independence. However, interstate squabbles and problems with assisting states who needed help against insurrection demonstrated that these Articles did not create a federal government with enough power. For this reason, the Continental Congress drafted the Constitution of the United States in 1787, introducing the official rules by which the new nation would be governed. The Constitution was officially ratified by nine states in 1788.