History is about arguments, arguments that we have about the past. The best history tells us something about ourselves as well as something about bygone times. This is particularly true of the new history of the American Civil War that has emerged—and is emerging—with the sesquicentennial of the great conflict.

During the past generation, one matter—slavery—has transformed the history of the Civil War. Once thought a minor aspect of a contest that was rooted in a dispute about the locus of political power (that is, the issue of states’ rights), or, at best, a subterfuge for evading the real issues of sectional differences respecting banks, railroads, tariffs, and land policy, slavery has emerged as the central cause of the war, as well as the primary determinant of its course and the terms of its settlement. Although the general public still seems fixed on the matter of states’ rights—nearly half of Americans, according to a recent Pew Research Center survey, believe it was the reason the war was fought—the focus on slavery has inspired a raft of new scholarship. That, in turn, tells us something about the American people at the beginning of the 21st century.

With this emphasis on slavery has come a new interest in the question of race, a focus no doubt reinforced by the election of America’s first black president. The meanings of both whiteness and blackness have come under scrutiny as historians have investigated the causes of the war, the transformation of the conflict from a war to maintain national unity into a war of liberation, and the nature of Reconstruction, the postwar arrangement that eventually affirmed the demise of slavery but preserved and enhanced the doctrine of white racial supremacy.

Perhaps nowhere do the new history of the Civil War and the renewed interest in the history of race come together better than in Eric Foner’s Pulitzer Prize–winning book 

The Fiery Trial: Abraham Lincoln and American Slavery

 (2010). Foner, whose histories of the origin of the Republican Party and Reconstruction have informed American political history for more than a generation, traces Lincoln’s evolution from a small-town racist—that is, a believer in the inferiority of people of African descent—to the Emancipator who, in the last year of the war, signaled a willingness to extend suffrage to black men.

 is that it provides a sense of how deeply and thoroughly the view that black people were inferior to whites pervaded American society. From this perspective, Lincoln’s embrace of emancipation and his willingness to imagine—however hesitantly and incompletely—an interracial America are all the more striking. Lincoln’s transformation, however, was neither direct nor easy. Foner’s genius is in exposing the process by which the president peeled away his old ideas and embraced new ones and in emphasizing the critical role black people—particularly black soldiers—played in this transformation. As Foner describes the development of Lincoln’s beliefs, he gives a sense of how the nation itself changed between 1857, when Chief Justice Roger Taney issued his opinion in the Dred Scott case (which held that black people were not citizens of the United States and “so far inferior that they had no rights which the white man was bound to respect”) and the ratification, in 1868, of the Fourteenth Amendment (which broadly defined American citizenship to include all born in the United States, black people among them).

If the war recommitted the nation to its founding egalitarian principles—Lincoln’s “new birth of freedom”—what happened to that commitment? In 

Race and Reunion: The Civil War in American Memory

 (2001), a powerful study of the struggle over the memory of the war, Yale historian David Blight explains how the wartime revolution was rolled back. For those who cheered the final demise of slavery and the advances of universal equality, the story of the postwar retreat from civil rights was not a pretty one. It is, however, every bit as gripping as the war itself.

Enlisting an extraordinary array of sources, Blight shows how the fight against slavery was written out of the history of the Civil War. In its place stood the myth of a gallant struggle between principled white men, North and South, whose shared belief in white supremacy overcame differences that once rankled the nation. As they wrote Jim Crow into law, purveyors of sectional reconciliation largely erased the campaign for black equality—and often black people themselves—from the history books. As Blight makes clear, while the new racial dispensation spoke of sectional comity, the process—both the sectional reconciliation and the new history that fostered it—was contested, as black people and their emancipationist allies resisted the new regime. In the end, the old racial order of white supremacy appeared with a new face. Race—the meaning of blackness and whiteness—which had been remade by the war, was remade again in the war’s aftermath.

In emphasizing the fluidity of racial ideas during the Civil War era, Foner and Blight raise the question of what exactly race meant to white Americans in the 19th century. For most scholars, the principle that embodied the American definition of race could be found in a rigid adherence to the one-drop rule, the notion that any measure of African ancestry made an individual black. For most white Americans, this truism, enshrined in law as well as custom, became the signature of the racial regime in the United States and the rule that distinguished it from other racial regimes in the Americas and elsewhere.

Recent work, however, casts doubt on the salience of the one-drop rule. In an ingeniously constructed study of judicial decisions involving racial identity—cases that determined if a person was legally white or not—Ariela J. Gross, a professor of law at the University of Southern California, argues that 19th-century white Americans cared far less about the one-drop rule than has been commonly thought. Her book 

What Blood Won’t Tell: A History of Race on Trial in America

 (2008) reveals that time and again, in cases of disputed racial identity, white American jurists chose to ignore evidence of black ancestry in favor of common reputation in the community. That is, if a person acted white—associated with white people, joined in the white community’s social and political life, and behaved in a manner that white men and women characterized as respectable—he or she would be deemed white, even in the face of evidence to the contrary. In short, whiteness was a matter of performance and not a product of heredity or a quotient of blood. In the United States, despite the numerous prohibitions on racial mixing and screeds against miscegenation (a word of American invention), white people did not treat race as a fact of nature but as a product of social interaction.

As they wrote Jim Crow into law, purveyors of sectional reconciliation largely erased the campaign for black equality - and often black people themselves - from the history books.

Other studies of the Civil War era that focus on the matter of race support Gross’s findings. One of the most telling is Joshua Rothman’s 

Notorious in the Neighborhood: Sex and Families Across the Color Line in Virginia, 1787–1861

 (2003). In a series of brilliant, iconoclastic essays, Rothman, a history professor at the University of Alabama, Tuscaloosa, provides an eye-opening view of race as it was regarded in antebellum Virginia. In one of his most notable pieces, he focuses on Charlottesville, then a small town just down the road from Thomas Jefferson’s Monticello. Nancy West, proprietor of the town’s largest bakery during the first decades of the 19th century, was—like several other Charlottesville residents, including a number of Jefferson’s children by Sally Hemings—the descendent of a white planter and a black slave woman. West lived openly with David Isaacs, a Jewish dry-goods merchant, with whom she had seven children, one of whom married Eston Hemings, the man whose DNA would eventually confirm Jefferson’s relationship with Sally Hemings.

The presence of West and Isaacs clearly grated on some of the town’s white residents, who were particularly irked by their practice of shuttling money back and forth between them to elude creditors. But when the couple were brought to court, charged with living in a lewd and lascivious relationship, the case quietly disappeared from the docket. Another charge, that West and Isaacs were engaged in an illegal

common-law marriage—perhaps self-evident given their seven children—likewise disappeared, suggesting that most white residents of Charlottesville had no objection to the presence of these two productive property holders, despite West’s color. Again, performance, not blood, determined race.

That is not to say that the laws respecting blood quotient—in Virginia, one black ancestor in four—were not of significance. The one-drop rule clashed constantly with the on-the-ground reality of race. As the sectional conflict heightened in the 1850s, these laws tangled in ways that revealed the absurdity of racial divisions, as Richmond courts formally denominated those who fell below the official threshold “not-a-Negro.”

The works of Ariela Gross and Joshua Rothman provide a suitable backdrop for an age when the black president of the United States travels to Ireland to celebrate his Irish ancestors and recover his lost apostrophe. In openly characterizing himself as a “mongrel,” President Barack Obama reflects a willingness of the American people to address the complexity of their country’s racial history and the war that, as Eric Foner and David Blight demonstrate, set it on a new course.

, a professor of history at the University of Maryland, College Park, has written extensively about slavery in America. His books include

 Generations of Captivity: A History of African-American Slaves (2002), Many Thousands Gone: The First Two Centuries of Slavery in North America (1999), 

 Slaves Without Masters: The Free Negro in the Antebellum South (1975).

Ira Berlin