Richard Nixon thought that doing it would make him look like a "jerk." Geraldine Ferraro said it spread germs and lipstick, but did it anyway. Andrew Jackson suckered his secretary of war into doing it for him. Davy Crockett did it so much it should have been mentioned in his theme song. We're talking about kissing babies, that revered yet reviled, much-analyzed yet meaningless American political custom.

Few candidates dare avoid it, yet no one can point to a case of a politician's failure to do it (or to do it well) causing an electoral defeat. As we head into the thick of another hotly contested baby-smooching season, here's a short history of our love-hate relationship with a campaign-trail cliché.

1833: Andrew Jackson's lips are sealed 

The first politician to lay lips on an unsuspecting infant is unknown, though President Andrew Jackson is credited with the first use of a supporter's baby as a political prop. As recounted in an 1888 issue of Cosmopolitan (no, not that one), during an 1833 tour of the eastern states, the president was approached by a "poor bareheaded woman with a little baby under her arm" who said she wished to see him...