In the discussions over Lee Circle and related monuments in New Orleans, one question has been raised that, because it’s a valid concern, deserves to be addressed with respect. That is the issue of the slippery slope. If we take down a monument to Robert E. Lee, where does it end? Ought we then take down the statue of Andrew Jackson, since he was a slave owner? Rename Washington and Jefferson avenues? Remove the statue of Bienville, since he wrote the first Code Noir that regulated the practice of slavery in the city he founded?

Renaming public places and moving monuments is often done, and it can indeed be a slippery slope. But pointing that out does not settle the argument. Most slopes are slippery. That realization should prompt us to figure out what principles we should use — what distinctions we should make — to find a secure foothold. If we become unwilling to navigate all slippery slopes, we will find ourselves comfortable only on the extremes of any issue, which is a problem that is afflicting our nation and world today.

One way to make distinctions and develop principles about different monuments is to look at their history. What was the purpose of the monument? Why was it erected? What message was it built to send?

Let’s consider, for example, the two most prominent monuments in the city, those to Jackson and Lee. Both involved renaming a beloved public space in response to sentiments of the time.

In 1851, the Place d’Armes was renamed Jackson Square and, five years later, 60,000 people jammed into it to celebrate the unveiling of Clark Mills’s statue of the general on his rearing horse. The intent of the monument was clear. It was to honor the man who had mustered in that square a motley assortment of troops — militiamen, Kentucky volunteers, slaves, free men of color, local gentry, Indians, pirates and privateers — to defend the city for America. It was, by the way, an inspiringly inclusive endeavor. Gov. William Claiborne gave Jackson approval to recruit blacks, and Jackson issued a special proclamation to them. “Through a mistaken policy,” he declared, “you have heretofore been deprived of a participation in the glorious struggle for national rights in which your country is engaged. This shall no longer exist.”

So whatever your views on Jackson’s overall career, the message of the monument was simple. It celebrated, and still does, someone who pulled us together to save New Orleans.

The monument to Robert E. Lee was erected in 1884 in what had been known for almost a century as the Place du Tivoli and then, after its corners had been rounded off, Tivoli Circle. It was a beloved gathering spot so named because its centerpiece was a carousel of flying horses. In many ways, it was an expression of the city: playful, a bit whimsical, with a whiff of European style. The decision to change it into Lee Circle came soon after the end of Reconstruction.

Many of those involved in the decision to build the Lee monument reflected the genuine sentiments of those who had fought under Lee or considered him, in the words proclaimed at the dedication, the “chivalric chieftain of the Lost Cause.” Their motives ought not be disparaged. But judging from the newspaper articles of the time, others saw the statue of Lee as a defiant symbol of white resistance and Southern rebellion.

Unlike Jackson, Lee had no direct connection to New Orleans. As far as I can tell, he never even visited the city. He is memorialized not because of his contributions to the city’s history nor as a way to send a message about our shared values.

Likewise, today there are varying motives among those who advocate retaining a prominently placed monument to Lee. Some supporters may be able to point to a great-great-grandfather who was there at Gettysburg at two o’clock on that fateful July afternoon in 1863 or who have other sincere reasons for wanting to commemorate the valor of the Confederate military or preserve the landmarks we grew up with. But some others, including those most prone to wave the Confederate battle flag during debates over the issue, seem to value the statue mainly as a defiant symbol of white resistance. No wonder the statue of Lee, unlike that of Jackson, sends mixed signals and arouses different emotions in our community.

Monuments exist for a purpose. That purpose is to convey a message. At a time when our public and Internet discourse has become coarser, more divisive and at times even hateful and intentionally hurtful, it’s useful to favor civic symbols that were originally, and still are, intended to be inclusive.

Walter Isaacson, a native of New Orleans, has written biographies of Benjamin Franklin, Albert Einstein and Steve Jobs.