(CNN) Amid the white supremacist-fueled violence over the weekend in Charlottesville, Virginia, and President Donald Trump's assertion that "both sides" bear responsibility for it, there's an active debate about whether any president has ever behaved like this before in the face of a national crisis. Hoping to find some answers -- and some much-needed historical context -- I reached out to Tim Naftali, a history professor at New York University. Naftali is also the former director of the Richard Nixon Presidential Library and is a CNN contributor. Our conversation, conducted via email and lightly edited for flow, is below.

Cillizza: Put Trump's comments about Charlottesville over the past four days into some sort of historical context? Has any modern president ever done anything like this before?

Naftali: In the turbulent Civil Rights and Vietnam era, some of our presidents showed moral cowardice in trying somehow to condemn hate without alienating haters in their political base -- John F. Kennedy after the Freedom Riders were attacked in May 1961 (he would redeem himself in June 1963), Richard Nixon after Kent State in 1970.

Donald Trump, however, took this cynical verbal gymnastics to a new low by being the first to equivocate in front of the cameras about a neo-Nazi/white nationalist march. There is no way that an American veteran of World War II, or frankly of any war, could or would have done that.

JUST WATCHED Naftali appeared on CNN with Fareed Zakaria over the weekend. Replay More Videos ... MUST WATCH Naftali appeared on CNN with Fareed Zakaria over the weekend. 07:34

Cillizza: Trump made an argument that getting rid of a Robert E. Lee statue starts us down a slippery slope of historical revisionism. As a historian, what's your response?

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