The most famous story about modern presidential campaigning now has a quaint old-world tone. It’s about the showdown between Richard Nixon and John F. Kennedy in the first debate of their 1960 campaign, which was also the very first nationally televised general-election debate in the United States.  

The story is that Kennedy looked great, which is true, and Nixon looked terrible, which is also true—and that this visual difference had an unexpected electoral effect. As Theodore H. White described it in his hugely influential book The Making of the President 1960, which has set the model for campaign coverage ever since, “sample surveys” after the debate found that people who had only heardKennedy and Nixon talking, over the radio, thought that the debate had been a tie. But those who saw the two men on television were much more likely to think that Kennedy—handsome, tanned, non-sweaty, poised—had won.  

Historians who have followed up on this story haven’t found data to back up White’s sight-versus-sound discovery. But from a modern perspective, the only surprising thing about his findings is that they came as a surprise. Today’s electorate has decades of televised politics behind it, from which one assumption is that of course images, and their emotional power, usually matter more than words and whatever logic they might try to convey.

The record of presidential debates since 1960 generally conforms to White’s maxim. In only a minority of cases have politicians gained or lost ground based on what they said, rather than how they looked while saying it. Gerald Ford is the most obvious example. In his second debate against Jimmy Carter in 1976, when Ford was fighting to hold on to the presidency he had assumed after Richard Nixon resigned, Ford said that Eastern Europe was not under the Soviet Union’s domination. The questioner threw him a lifeline, with an incredulous “Did I hear that right??” follow-up. But Ford ignored the signal and gave a longer, more definitive statement of the same view. Despite his stumblebum image, Ford, a Yale Law School graduate, was no dummy, and what he meant made sense. He was trying to say that the indomitable spirit of the Poles could never be crushed, and that the United States would never concede the status of Eastern European countries like Poland as mere Soviet satellites. So through the rest of the debate, while on camera before tens of millions of viewers, Ford betrayed no awareness that anything had gone wrong. (I was on Carter’s campaign staff then, and was there.) It was only afterward that he learned this was a “gaffe,” one that would dog him for the rest of his campaign and even show up in his obituaries.

That was an exception. The rule is that the way candidates react, immediately and usually involuntarily, while caught by the camera, dominates impressions of who has “won” or “lost” an encounter. This is why the most accurate way to predict reaction to a debate is to watch it with the sound turned off.