By the 1750s, the thirteen English colonies had grown large and used to running their own affairs. Then Britain fought France for control of North America and won, in 1763. The war left Britain deep in debt, and Parliament decided the colonies should help pay. It taxed stamps, paper, tea — and the colonists exploded. Their argument was simple: they had no vote in the Parliament that taxed them. No taxation without representation.
Protest grew into resistance. In 1773, men boarded British ships in Boston harbor and threw the tea into the water. Britain punished Boston; the colonies united behind it. In April 1775, at Lexington, Massachusetts, someone fired a shot, and the war began.
In July 1776, the Continental Congress declared independence. The Declaration of Independence did more than say goodbye to a king. It stated a theory of government: that all men are created equal, and that governments get their power from the consent of the governed — the agreement of the people they rule. Its main writer, Thomas Jefferson, enslaved more than a hundred people while he wrote those words. Hold that contradiction. It is not a footnote to this story; the rest of the story is a long fight over it.
The war lasted eight years. France joined the American side, and in 1781 a British army surrendered at Yorktown, Virginia. In 1783, Britain recognized the United States as an independent nation. Winning the war turned out to be the easy part.
The first plan of government, the Articles of Confederation, was built weak on purpose — nobody wanted a new king. It was too weak to work. The national government could not tax, could not pay its soldiers, and could barely respond when indebted farmers in Massachusetts rose up in arms. The country that had survived a war was failing in peacetime.
So in the summer of 1787, delegates met in Philadelphia and wrote the Constitution — the written plan for the American government, still in force today. These were men who had just overthrown a king and were afraid of accidentally building another. So they split power three ways: a Congress to make the laws, a president to carry them out, courts to judge by them — and they set each branch to check the others. Then they split power again, between the national government and the states. Every piece of the design answers a specific fear. Learn the civics that way, as answers to fears, and it stays learned.
One thing was missing. When the states debated the Constitution, people demanded a written list of their rights. In 1791 the first ten amendments — additions to the Constitution — were adopted, and together they are called the Bill of Rights: freedom of speech, of the press, of religion; the right to gather and to protest; protection against unreasonable searches; the promise of a fair trial. None of it appeared by itself. People argued it into the document, and people have been fighting over what it means ever since.