On September 17, 1787 delegates from the thirteen states meeting in a special convention in Philadelphia, Pennsylvania voted to adopt a new constitution. The delegates had been sent to Philadelphia to make changes to the Articles of Confederation, but instead had exceeded their authority and decided to create an entirely new form of government. Rather than having a confederation of independent states, the new constitution called for the establishment of a federal government that would unite the states into one nation.
The new constitution still needed to be ratified by the people and the states. It was decided that rather than a needing a unanimous ratification it would require passage by only nine of the thirteen states. Constitutional conventions were called in all thirteen states and representatives were sent to say yea or nay to the constitution.
As soon as news went out from Philadelphia about the results of the convention the controversy began. Many of the people who had fought the hardest to gain independence for the thirteen American colonies were steadfastly against having the new Federal form of government. The Anti-Federalists, as they were called, were deathly afraid of trading one set of masters for another. They were concerned that putting too much power in the hands of a central government would lead to that power being abused.
The framers of the Constitution were also aware of the danger of too much power being placed in the hands of government. They quite deliberately built into the Constitution a series of checks and balances that was meant to limit the extent and the power of the government. The Federal government they established had three co-equal bodies - the executive branch, the legislative branch and the judiciary. Each body was meant to provide a "check" on the power of the other two bodies. The specific powers of each branch of government was laid out and the powers not given to the Federal or State governments were meant to stay with the people.
With many people believing that the Constitution as written didn't go far enough to protect the rights of the people, a number of amendments were proposed. Ten of these proposed amendments, which came to be known as the "Bill of Rights", were added to the Constitution and became part of the ratification process. Since then some 17 other amendments have been added to the Constitution.
The arguments of the Federalists held sway in the country and the U. S. Constitution was ratified. With New Hampshire voting on June 21, 1788 to ratify, the required number of states was reached. On March 4, 1789 the Constitution went into effect and it remains as the oldest written constitution governing a democratic nation in the world.