Though the U.S. Constitution was ratified in 1788, its impact on our lives is as recent as today's news. Claims and counterclaims about the constitutionality of governmental actions are a habit of American politics. This document, which its framers designed to limit power, often has made political conflict inevitable. It also has accommodated and legitimized the political and social changes of a vibrant, powerful democratic nation. A product of history's first modern revolution, the Constitution embraced a new formula for government: it restrained power on behalf of liberty, but it also granted power to promote and protect liberty. The U.S. Constitution: A Very Short Introduction explores the major themes that have shaped American constitutional history- federalism, the balance of powers, property, representation, equality, rights, and security. Informed by the latest scholarship, this book places constitutional history within the context of American political and social history. We do not operate today under the same Constitution created by our founding fathers or the Constitution as completed by the Bill of Rights in 1791 or even the one revised by the Reconstruction amendments. Nor are we the same nation. As our circumstances have changed, so has our Constitution. Today we face serious challenges to the nation's constitutional legacy. Endless wars, a sharply divided electorate and deadlocked government, economic inequality, immigration, cybersecurity and privacy, and foreign interference in the nation's democratic processes, among a host of other issues, have placed demands on government and on society that test our constitutional values. Understanding how the Constitution has evolved will help us adapt its principles to the challenges of our age.