When did the U.S. government officially begin operating under the U.S. Constitution?

The U.S. government officially began operating under the U.S. Constitution on March 4th, 1789. This date marks the commencement of the first Congress under the Constitution, as well as the inauguration of George Washington as the first President of the United States.

The Constitution was drafted in 1787 and was subsequently ratified by the states, but it did not take effect until the new government was established. The date signifies the actual implementation of the framework laid out in the Constitution, transitioning from the Articles of Confederation to a more effective federal structure. This moment is pivotal in U.S. history, as it marks the beginning of a government designed to address the weaknesses of the previous governing document and to create a system of checks and balances among the branches of government.

Understanding this date is crucial in recognizing the evolution of American governance from theoretical frameworks to practical application, which is central to the study of U.S. history and law.