Written for Facebook:
I've covered the ugly, racist "heritage" represented by the Confederate flag. That's what's being celebrated by those who revere it, whether they recognize it or not. But that "whether they recognize it or not" part is a rather complicated matter, one not typically treated with much sensitivity by internet flame-wars.
The Confederate states had launched what became the most murderous war in U.S. history and nearly destroyed themselves. Defeat was a bitter pill that had to be swallowed but the fact that all of it had been done in the name of such an utterly disreputable cause was, for far too many, simply more than they were willing to acknowledge. In the years after the war, various writers in the South began to craft a self-serving mythology that has been dubbed the "Lost Cause." It portrayed the antebellum South as a sort of beautiful paradise of chivalrous Christian gentlemen and genteel Southern belles sipping mint juleps on the porch while smiling, contented darkies worked the land. Slavery was a benign institution--loyal simpletons, living out their God-given station in life while overseen by benevolent masters. Far from being fought for its preservation, the war was a noble effort at self-defense by saintly warriors out to defend freedom and resist tyrannical government encroachment. The mythologists ubiquitously described the Confederates as the true heirs of the American revolutionaries.
This mythology began to develop almost immediately after the war's end and, in fact, drew from even older pre-war Southern cultural self-mythologizing (to an extent that, in my view, is underappreciated but that's a different topic). As it evolved, it encompassed the Reconstruction era; the popular image of rapacious Yankee carpetbaggers descending on the prostrate South while radicals, aided by scoundrelous scallawags, empowered corrupt, iniquitous governments across the former Confederacy in order to extend their own power and profit is a product of it. The post-war Ku Klux Klan--in reality, perhaps the most violent terrorist movement that has ever operated on U.S. soil and the first that could accurately (if anachronistically) be dubbed fascist--was a noble enterprise to defend the Southern way of life from these interlopers who sought to destroy it.
This entirely self-serving blend of half-truths, misrepresentations and fanciful fabrications proved incredibly popular in the South. Organizations like the Southern Historical Society, the Sons of Confederate Veterans and the United Daughters of the Confederacy (the latter of which became particularly powerful) sprang to life, the promotion of the myth being among their central goals. They wrote, lectured, created monuments, museums, successfully lobbied for laws requiring that history textbooks reflect the mythology and created blacklists of books that failed to do so. Mildred Lewis Rutherford of the UDC--a teacher from Georgia who became one of the best-known "historians" of her age--spent much of her life as an apostle of the myth, which had become a full-blown ideology (a series of them, really) that broke the bounds of the South. In 1915, D.W. Griffith directed THE BIRTH OF A NATION, a film based on the revisionist novel "The Clansman" by Thomas Dixon Jr. With its images of mounted Klansman heroically riding to the rescue against villainous Reconstruction reformers, it became a smash hit, the first American film ever screened in the White House (for then-president Woodrow Wilson) and a major factor in the 20th century rebirth of the Ku Klux Klan, which used it as a recruiting tool for years. In 1936, Margaret Mitchell published "Gone With The Wind," which became a massive bestseller, netted for her the Pulitzer Prize for Fiction and became one of the most popular representations of this mythology ever created. Until, that is, the movie version was released in 1939. The film took Best Picture at the Academy Awards and became the biggest box-office success in cinema history, a title it still holds 76 years later.
Pro-Confederate ideology has continued to mutate and evolve. As Americans began to come to terms with the unvarnished horrors of slavery, one doesn't hear as much from Confederate apologists about those "contented darkies" (although they're still around in some quarters). As a counter, a significant apologist literature has developed around the longstanding myth of black Confederate soldiers who willingly took up arms in defense of the Confederacy, sometimes said to number in the tens of thousands. The actual number: zero (I'll be dealing with this matter later). Other apologists have tried to get around slavery by focusing on Confederate legalistic arguments, taking the position that the Confederate states had a "right" to secede and, in rather Orwellian fashion, casting those states as defenders of free association standing against tyranny.
In the century-and-a-half since the war, elements of this long-nurtured Lost Cause mythology have taken very deep root in the U.S., particularly in the South. The perceptions of many--probably most--who revere the Confederate flag have been shaped by generation after generation of this propaganda; they don't even realize their view of the matter is a product of carefully cultivated fictions. Others fancy the romanticism of the mythology, which can seem particularly appealing in the increasingly oppressive present. A growing contingent of rightists simply see history as a weapon to be used in contemporary political disputes and don't really care about the truth. There are lots of reasons why people cling to the flag besides simply looking to glorify a white supremacist cause (though those looking to do that are yet another faction who cling to it). If any reasoned discussion is going to proceed, recognizing this is essential. There's no doubt the arrogance bred with ignorance one so often receives from those who brandish the flag brings down a lot of scorn and contempt by those more familiar (or more concerned) with the history in this matter but the other side of that coin is that not every fellow--and not, in fact, most fellows--waving the flag is some dim-witted racist.