NEW YORK — President Trump made puzzling claims about Andrew Jackson and the Civil War in an interview, suggesting he was uncertain about the origin of the conflict while claiming that Jackson was upset about a war that started 16 years after his death.

Trump, who has at times shown a shaky grasp of U.S. history, said he wonders why issues “could not have been worked out” in order to prevent the secession of 11 Southern states and a war that lasted four years and killed more than 600,000 soldiers.

“People don’t realize, you know, the Civil War, if you think about it, why?” Trump said in an interview with The Washington Examiner, according to a transcript released Monday. “People don’t ask that question, but why was there the Civil War? Why could that one not have been worked out?”

Trump ruminated after lauding Jackson, the populist president whom he and his staff have cited as a role model. He suggested that if Jackson had been president “a little later, you wouldn’t have had the Civil War.”

“He was really angry that he saw what was happening with regard to the Civil War. He said, ‘There’s no reason for this,”‘ Trump continued.

But Jackson died in 1845, and the Civil War didn’t begin until 16 years later, in 1861.

Jackson was a slave-holding plantation owner. Some historians do credit him with preserving the union when South Carolina threatened to secede in the 1830s over an individual state’s ability to void federal tariffs. That controversy, though, was not about slavery, and the eventual compromise that preserved states’ rights is viewed as a milestone on the way to the Civil War.