The Freedom Today, I'd want to start with a single instance in the history of American liberty. The Freedom Train debuted in Philadelphia on September 16, 1947, the 160th anniversary of the writing of the United States Constitution. The train, dressed up in red, white, and blue and carried a traveling exhibition of 133 historical documents, set off on a 16-month trip that took it to nearly 300 American towns. Never before have many essential elements of American history been brought together in one spot, including the Pilgrims Treaty, Declaration of Independence, and Harrisburg Address. Visitors were encouraged to pledge their allegiance to American principles by signing the Freedom Pledge and adding their names to a Freedom Scroll after exiting the train. Indeed, black Americans had almost little said in the exhibition's preparation, and many were apprehensive at first. The poet Langston Hughes voiced his wish for "no Jim Crow aboard the Freedom Train" on the eve of the train's debut. "When it stops in Mississippi," Hughes wondered, "will it be made plain/ Everybody's got a right to board the Freedom Train?" Indeed, with the Truman administration set to make racial rights a top priority, the train's organizers declared that segregated viewing would be prohibited. The American Heritage Foundation postponed visits to Memphis and Birmingham in an unusual move when local officials insisted on dividing visitors by race. The narrative of the Freedom Train is told in one of the chapters in my new book. The Story of American Freedom, which explores the concept of liberty in the United States from the Revolution to the present. I start with it today because it demonstrates in miniature my central premise: that the idea of freedom, far from being set, is a source of ongoing contention in American history. It also emphasizes the three key concerns that have dominated arguments about freedom in the United States in the past: the meaning or definition of freedom, the social conditions that enable freedom, and the bounds of freedom, or who is entitled to enjoy it. Freedom is an essential concept in Americans' sense of self as individuals and in society. The primary phrase in our political lexicon, freedom — or liberty, as it is nearly often referred to is firmly ingrained in both the historical record and the language of ordinary life. The Declaration of Independence mentions liberty as one of humanity's intrinsic rights, and the Constitution declares that it is the goal of the government to provide liberty's benefits. The Civil War was fought to bring about a new birth of freedom, World War II was fought to protect the Four Freedoms, and the Cold War was fought to defend the Free World. "Operation Iraqi Freedom" is indeed the name given to the present conflict. It is not historians' responsibility to teach our fellow citizens how to think about freedom. However, it is our responsibility to ensure that discussions about freedom transcend rather than reinforce or reproduce barriers. From my vantage point in 2003, it appears like the next 100 years will be even more of an American century than the previous one. This emphasizes the importance of turning the unfinished tale of American liberty into a discussion with the entire world rather than a smug monologue with ourselves. If September 11 inspires us to think historically, rather than mythically, about our country and its place in the world, then the tragedy will have served a purpose.