Whenever I read polls about a forthcoming U.S. election, the 1980 election in which Ronald Reagan and the Republicans swept the board and changed the country springs to mind.

But that vote didn’t break the Republicans’ way until the final weekend before election day.

The late Sen. John Culver of Iowa, who lost in that Reagan landslide to the still-in-office Sen. Chuck Grassley, told me afterward that he and other Democrats who lost then didn’t pick up on the electorate’s negative feelings until the Saturday before the vote. Then-President Jimmy Carter and his entourage only realized the Saturday night before the Tuesday vote that he was going to be defeated.