T.J. Stiles, an historian whose biography of Gen. George Custer won the Pulitzer Prize for History in 2016, found himself dumbfounded by the ignorance former President Donald Trump displayed when he talked about the American Civil War over the weekend.

In particular, Stiles said that Trump's rant about the Battle of Gettysburg during his rally in Pennsylvania was so historically illiterate that he began his analysis of it by simply saying, "Hoo boy."

Stiles took a hatchet to Trump's depiction of Gen. Robert E. Lee as a passive observer during the battle, when in reality it was Lee's decisions that led to disaster for the Confederacy.

"Trump's rambling, unhinged depiction of Lee is that of a great general betrayed by his stupid troops," Stiles wrote on Twitter. "You'd never know he gave the orders for the campaign and battle. He said after Pickett's charge that it was all his fault. It was."

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Stiles also whacked Trump for depicting Lee as a noble man despite the fact that Lee's goal was to destroy the American Union.

"Let's think it through: How can saving the Union be good -- but the guy who tried to destroy it be good too?" Stiles asked rhetorically. "Worse than that, Lee issued orders on the Gettysburg campaign for his troops to enslave all the Black people they could find—not just 'runaways' but those born free. A system was set up for processing them. Of the many things the campaign was, it was also a big slave raid."

Stiles then drew parallels between the history of the American Civil War and current events.

"Many still have a vague notion in their heads of Civil War history written by segregationists a century ago to serve an agenda," Stiles contended. "It serves Trump's agenda too."

Read the whole thread here.