By the 1820s, most states began to pass laws allowing voters, not state legislatures, to choose electors on a winner-take-all basis.

Mr. Trump’s strongest supporters are the 21st-century heirs of a political tendency that coalesced in the early 1820s around Andrew Jackson.

By the 1820s, democracy itself had become too elemental a force to be checked or to need the promotion of any one man.