How memorable debate moments are made: on the fly, rehearsed — and sometimes without a word uttered

It's debate prep time for President Joe Biden and Republican Donald Trump, and their teams are no doubt looking back at how past memorable debate moments came together, for good or ill. Those signature moments may be well-rehearsed zingers or offhand reactions like a too-loud sigh or a glance at a wristwatch. Past debates demonstrate how the candidates’ words and body language can make them look especially relatable, or hopelessly out-of-touch. They can also showcase candidates at the top of their policy game — or provide an indication they're out to sea. As one debate expert put it, “Anything can happen.”