In one of his latest interviews, President Trump sparked confusion—and ridicule—by questioning why, exactly, the Civil War was fought, and suggesting former President Andrew Jackson could have averted the war itself—had he not been dead for 16 years by the time it began.

President Donald Trump: “I mean, had Andrew Jackson been a little bit later, you wouldn’t have had the Civil War. He was—he was a very tough person, but he had a big heart. And he was—he was really angry that he saw what was happening with regard to the Civil War. He said, ’There’s no reason for this.’ People don’t realize, you know, the Civil War—”

Salena Zito: “Yeah, was—”

President Donald Trump: “You think about it, why? People don’t ask that question. But why was there the Civil War? Why could—why could that one not have been worked out?”

The Civil War was fought over the expansion of slavery in the United States. President Jackson was a slaveholder. Princeton University history professor Julian Zelizer said Trump’s comments were the “height of inaccurate historical revisionism.” Trump later doubled down on his statements, tweeting on Monday night, “President Andrew Jackson, who died 16 years before the Civil War started, saw it coming and was angry. Would never have let it happen!”