The strangest part about the continued personality cult of Robert E. Lee is how few of the qualities his admirers profess to see in him he actually possessed.

Memorial Day has the tendency to conjure up old arguments about the Civil War. That’s understandable; it was created to mourn the dead of a war in which the Union was nearly destroyed, when half the country rose up in rebellion in defense of slavery. This year, the removal of Lee’s statue in New Orleans has inspired a new round of commentary about Lee, not to mention protests on his behalf by white supremacists.

The myth of Lee goes something like this: He was a brilliant strategist and devoted Christian man who abhorred slavery and labored tirelessly after the war to bring the country back together.

There is little truth in this. Lee was a devout Christian, and historians regard him as an accomplished tactician. But despite his ability to win individual battles, his decision to fight a conventional war against the more densely populated and industrialized North is considered by many historians to have been a fatal strategic error.

But even if one conceded Lee’s military prowess, he would still be responsible for the deaths of hundreds of thousands of Americans in defense of the South’s authority to own millions of human beings as property because they are black. Lee’s elevation is a key part of a 150-year-old propaganda campaign designed to erase slavery as the cause of the war and whitewash the Confederate cause as a noble one. That ideology is known as the Lost Cause, and as historian David Blight writes, it provided a “foundation on which Southerners built the Jim Crow system.

There are unwitting victims of this campaign—those who lack the knowledge to separate history from sentiment. Then there are those whose reverence for Lee relies on replacing the actual Lee with a mythical figure who never truly existed. ...