President Donald Trump questioned why the US Civil War was not "worked out" peacefully and suggested Andrew Jackson could have prevented the deadly conflict if he had lived later.
In an interview published on Monday Mr Trump praised the accomplishments of Jackson, the populist 19th Century president he has cited as a role model.
Speaking to the Washington Examiner, Mr Trump said: "I mean, had Andrew Jackson been a little later, you wouldn't have had the Civil War. He was a very tough person but he had a big heart, and 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 realise, you know, the Civil War, you think about it, why? People don't ask that question, but why was there the Civil War? Why could that one not have been worked out?"
President Andrew Jackson, who died 16 years before the Civil War started, saw it coming and was angry. Would never have let it happen!— Donald J. Trump (@realDonaldTrump) May 2, 2017
Jackson died in 1845 and the Civil War did not begin until 1861, some 16 years later.
Amid suggestions from critics that Mr Trump had made a historical error supporters defended his remarks, pointing out that the war was decades in the making stemming from long disputes between the North and South about slavery and states' rights.
"President Andrew Jackson, who died 16 years before the Civil War started, saw it coming and was angry. Would never have let it happen!" Mr Trump said on Twitter late on Monday.
Mr Trump has long been an admirer of Jackson, the seventh US president, calling himself a "fan" of a president who "confronted and defied an arrogant elite".
He described a recent visit to Jackson's estate in Tennessee as "inspirational" and even visited his wife's grave.
Mr Trump told the Washington Examiner: "They said my campaign and win was most like Andrew Jackson with his campaign. He had a very, very mean and nasty campaign.
"His wife died. They destroyed his wife and she died. And, you know, he was a swashbuckler. But when his wife died, you know, he visited her grave every day."