In an essay on “America's Shakespeare” at National Interest, Algis Valiunas traces the shifting political of Shakespeare in the US.

Whitman initially thought Shakespeare was “poisonous to the idea of the pride and dignity of the common people, the life-blood of Democracy.” Further study of the history plays led him to the conclusion that Shakespeare was a good American democrat after all. By exposing the evils of medieval kingship, Shakespeare wrote “the first full exposé…of the political theory and results, or the reason-why and necessity for them which America has come on earth to abnegate and replace.”

Lincoln rarely without his Shakespeare. He “toted Shakespeare along on his rounds of the judicial circuit; his son remembered him with a copy of Shakespeare in hand as he went about his business in the White House; his secretary John Hay listened to the president’s midnight declamations of favorite Shakespearean passages; and Lincoln dipped into Hamlet to fortify the eloquence of his first inaugural address. But his favorite play was—a portentous choice—Macbeth.”

John Wilkes Booth's imagination was sparked by another play. He was “most celebrated as Antony in a performance of Julius Caesar with his two more distinguished brothers that was hailed as ‘the greatest theatrical event in New York history.'” He was still living in Julius Caesar when he killed Lincoln: “Booth had written a letter on the day of the assassination, addressed ‘To My Countrymen' and intended for newspaper publication, in which his peroration roars with Shakespearean thunder: ‘When Caesar had conquered the enemies of Rome and the power that was his menaced the liberties of the people, Brutus arose and slew him. The stroke of his dagger was guided by his love for Rome. It was the spirit and ambition of Caesar that Brutus struck at. ‘O then that we could come by Caesar’s spirit,/ And not dismember Caesar! But alas!/ Caesar must bleed for it!'”