President Trump mused in an interview that the Civil War could have been avoided if only Andrew Jackson had been around to stop it. Jackson had been dead 16 years and long out of office when the war started in 1861.

Mr. Trump’s comments, among several he made about Jackson in an interview broadcast Monday on satellite radio, quickly drew condemnation from his critics and from historians who said they appeared to show the president profoundly misunderstanding American history.

“People don’t realize, you know, the Civil War, if you think about it, why?” he told his interviewer, Salena Zito, a host on SiriusXM’s P.O.T.U.S. channel, who spoke to Mr. Trump for an article that was published on Sunday in The Washington Examiner.

Mr. Trump followed up on the comment in a tweet on Monday night, arguing that Jackson saw the Civil War coming and would have prevented it had he not died 16 years earlier.