David A. Bell, a professor of French history at Princeton, is the author, most recently, of “Shadows of Revolution: Reflections on France, Past and Present.”

Workers prepare to take down New Orleans’s statue of Confederate Gen. Robert E. Lee on May 19, 2017. (Gerald Herbert/Associated Press)

George Washington and Thomas Jefferson owned slaves. No less a figure than Abraham Lincoln said: “I have no purpose to introduce political and social equality between the white and black races. There is a physical difference between the two, which, in my judgment, will probably forever forbid their living together on the footing of perfect equality.” Woodrow Wilson was a staunch segregationist. All of them held the highest office in a nation that denied women the right to vote until 1920 and denied gays and lesbians the right to marry until 2015. Should we, as a country, still be honoring these men today?

That’s the question that we’ve grappled with, anew, since Saturday’s tragic events in Charlottesville and President Trump’s subsequent response, but it’s not a new one. Two years ago, students at Princeton University, where I teach, occupied the college president’s office to demand that the name of Wilson — our most famous alumnus and a former Princeton president — be removed from our school of public policy and international relations and an undergraduate housing complex. This year, Yale University announced that it would rename a residential college named for Vice President John C. Calhoun, a fervent defender of slavery.

It is easy to take the position that Trump did, effectively, on Wednesday, when he tweeted, “Can’t change history, but you can learn from it. Robert E Lee, Stonewall Jackson — who’s next, Washington, Jefferson? So foolish!” After all, the argument goes, weren’t these iconic figures simply men of their time? Weren’t their opinions and practices entirely ordinary for their social and political milieus? By the same logic, Trump implies, we should still respect the memory of figures like Gen. Robert E. Lee, the statue of whom the Charlottesville City Council recently voted to remove. Indeed, in an NPR-PBS NewsHour-Marist poll released Wednesday, 62 percent of respondents said statues honoring leaders of the Confederacy should remain as historical symbols.

But Trump’s rationale falls short for two reasons.

First, while slavery may have been utterly ordinary in Washington’s time, and overt racial discrimination equally commonplace in Lincoln’s and Wilson’s, neither was universally defended at the time. Even in the 18th century, for those with ears to hear, numerous voices were making reasoned, impassioned cases against slavery. If a prominent American revolutionary like Benjamin Rush — friend of John Adams and signer of the Declaration of Independence — could conclude that slavery was a direct violation of the laws of nature and religion, why not Washington or Jefferson?

Second, the argument that these men were just men of their time is an example of something that political conservatives otherwise generally profess to loathe: moral relativism. The idea that different standards of truth and morality may obtain in different times and places. Few people in the United States today would defend the practice of female circumcision, for instance, even though it is entirely ordinary in some parts of the world. Most people would say that no matter how customary, or perhaps even virtuous, this practice may seem to its adherents, it is, in fact, an affront to human dignity and human rights. Was slavery any less of an affront? No.

In the end, if we are to have any confidence in our own moral standards, we must believe that these standards are universally applicable, across time and space. And so, we must be ready to criticize figures in the past for attitudes and practices we consider abhorrent. If our moral standards are to have any meaning, then they don’t simply apply because we believe in them. They apply because they are right.

Yes, we also need to acknowledge that an overly rigid application of this principle would soon leave us with very little history to honor and celebrate, because few, if any, prominent figures of the past lived up to the moral standards of 21st-century Americans. Taken to the extreme, it would, indeed, mean tearing down the Washington Monument, and perhaps even the Lincoln Memorial.

But countries need their history. They need heroes and leaders to venerate, to inspire new generations, and to act as a source of unity. National unity can be a very fragile thing, as Americans today know all too well. Revolutionary movements have sometimes tried to consign their national pasts to the dustbin of history and to start over. The French revolutionaries famously introduced a new calendar, numbering the years from the birth of the French republic in 1792 and condemning nearly all of what came before as darkness, feudalism and superstition, unworthy of veneration. It didn’t work. Such attempts at erasure go against the deeply human need to feel a connection with the past.

The conflict, then, is one between two principles. On one hand, we should not honor people who did things and held beliefs that were morally objectionable. On the other, we need a common history we can take pride in as a nation. It is a conflict that cannot be resolved with cheap sound bites of the sort uttered by the president and his backers this week. They can be resolved only with careful, reasoned judgments, backed up by logic and evidence.

When it comes to particular figures in the past, such judgments involve, above all, looking carefully at their entire historical record. In the case of Washington, it involves weighing his role as a slave owner against his role as a heroic commander in chief, as an immensely popular political leader who resisted the temptation to become anything more than a republican chief executive, and who brought the country together around the new Constitution. Calhoun, by contrast, devoted his political career above all to the defense of slavery. The distinction between the two is not difficult to make.

Lee’s case is clear-cut. Whatever admirable personal qualities he may have had, he was also a man who took up arms against his country in defense of an evil institution. In my view, he doesn’t deserve to be honored in any fashion.

There are many historical figures in the American past whose overall record is complex, difficult and deeply ambiguous — Wilson comes to mind. But reasonable people can come to different judgments about them. Accepting the need for a past we can take pride in also imposes on us the duty to take history seriously.

We must always be ready to go back to the sources, to read, think and discuss. Our history is neither a monstrosity to be exorcised nor an altar to worship at. It is the record of the actions of millions of imperfect human beings. Deciding whom to honor and whom to condemn in this record requires more than 140 characters. It requires serious thought and discussion. As citizens today, that’s what we owe to the past.