People rally for the Confederate flag to be taken down, at the South Carolina State House last month. (John Taggart/EPA)

Hugh Howard is the author of “Houses of Civil War America.”

With astonishing speed — and a surprising new consensus — the status of the Confederate battle flag has been altered. While a reconsideration of that symbol’s original meaning is long overdue, there is a countervailing risk that the righteous satisfaction in some quarters at lowering the flag may blind us to another large misunderstanding of the past.

The conversation in recent days has been illuminating, as many politicians from the South try to navigate a historic landscape blurred by generations of distortions. With the abruptness of cataract surgery, “Lost Cause” interpretations of a genteel Southern past have fallen away. The denials that, in the Confederacy, the impetus for war was slavery have long rung false; the minutes of the secession conventions held in Southern states make that explicit (as one Mississippi advocate put it in 1861, “slavery was ordained by God and sanctioned by humanity”). Acknowledging that the Confederate flag symbolized the fight to extend human bondage can at last put to rest an enduring falsehood in our national memory.

As important as this corrective may be, we will do our historical memory a disservice if we fail to recall how citizens of the Union regarded Abraham Lincoln’s War, slavery and even African Americans. To a surprising extent, the way the North remembers the Civil War is also deeply flawed and misleading.

Recall that when Lincoln took office, slavery had the official sanction of the U.S. government. Like it or not, slavery was a part of the economic history of the North as well as the South. Much of the nation’s cotton, its largest export, was taken north of the Mason-Dixon Line to be processed; for that matter, many of the South’s most successful planters were Yankees who adopted with alacrity the practice of slavery on their way to wealth.

In the antebellum years, there was nothing resembling an anti-slavery consensus in the North. America’s greatest philosopher, Ralph Waldo Emerson, hesitated for years to decry what he called “the habit of oppression.” When he finally did so from the podium in Concord Town Hall, he was called a fanatic and worse. The word “abolition” made his neighbors angry. The idea rang radical even in Massachusetts, where many regarded those who espoused such views as dangerous.

It’s simply wrong-headed to presume that average, mid-19th-century farmers and factory workers in the North harbored abolitionist sympathies. They didn’t.

I was taught growing up in Yankee Massachusetts that the North went to war to end slavery, but since then I have come to understand that I was misinformed. A case in point is the story of the well-known primitive painter Robert Peckham. He had served as a deacon in the same Congregational church that I attended as a child in central Massachusetts. But archival research reveals that, in 1850, when Deacon Peckham espoused abolitionist sentiments, the church fathers excommunicated him, declaring one of their own unwelcome because they thought his ideas too extreme. Little Westminster represented a quiet majority opinion in the region.

Even Lincoln’s racial thinking evolved in a slow and ambiguous manner. Until the very end of his life, the hero of the age resisted the notion that the black and white races were equal. In his famous 1858 debates — and elsewhere — he repeatedly rejected the idea of permitting black men to vote, serve as jurors, hold office or intermarry with whites. “There is a physical difference between the two, which, in my judgment, will probably forever forbid their living together upon the footing of perfect equality.”

That meant that, at its outset, the war for Lincoln was explicitly about union — until it became expedient to make it about emancipation. The Emancipation Proclamation was primarily intended to hobble the Confederacy’s war effort, which relied upon slaves for provisioning and other support.

Even among those who recognized that human bondage must end, few thought blacks were equal to whites. In the South, where 95 percent of the nation’s African Americans resided, slavery had been a fact of life for generations, fixing the black man’s inferiority in the minds of most whites. In the North, where less than 1 percent of the population was black, relatively few whites interacted with men or women of color; there, anyone of African descent remained very much other.

The past is no more a fixed destination than the future is, and we need to question constantly the history we’ve been handed. One encounters such proper names as Reconstruction, Jim Crow, Selma and, now, Clementa Pinckney. But even as our outrage simmers at what made possible the allegedly murderous ignorance of Dylann Roof, we would do well to consider that, aside from the color of some of the players’ skins, there is little that is black and white about our terrible Civil War and the enduring legacy with which we must still wrestle.