The Declaration of Independence announced equality as an American ideal, but it took the Civil War and the subsequent adoption of three constitutional amendments to establish that ideal as American law. The Reconstruction amendments abolished slavery, guaranteed all persons due process and equal protection of the law, and equipped black men with the right to vote. They established the principle of birthright citizenship and guaranteed the privileges and immunities of all citizens. The federal government, not the states, was charged with enforcement, reversing the priority of the original Constitution and the Bill of Rights. In grafting the principle of equality onto the Constitution, these revolutionary changes marked the second founding of the United States.

Eric Foner's compact, insightful history traces the arc of these pivotal amendments from their dramatic origins in pre–Civil War mass meetings of African-American "colored citizens" and in Republican party politics to their virtual nullification in the late nineteenth century. A series of momentous decisions by the Supreme Court narrowed the rights guaranteed in the amendments, while the states actively undermined them. The Jim Crow system was the result. Again today there are serious political challenges to birthright citizenship, voting rights, due process, and equal protection of the law. Like all great works of history, this one informs our understanding of the present as well as the past: knowledge and vigilance are always necessary to secure our basic rights.