Barack Obama's ascension to the highest elected office in America's land is surely a milestone in the American narrative. The events of Nov. 4, 2008, and Jan. 20, 2009, are marks of America's collective progress. In the course of the long campaign season, however, there is another date that also should be etched into American textbooks: March 18, 2008. On that day, in Philadelphia, then-Senator Obama delivered a landmark speech on race. Titled "A More Perfect Union," the speech was, as one commentator put it, "refreshing" in that a political candidate ushered in "a serious conversation about America's challenges as a people. One important role of a leader is to serve as an educator, clarifying how Americans have arrived where they are and what their choices are as they look toward the future." An excerpt of "A More Perfect Union" is presented.