 At one point, President Biden reminding the audience of Mr. Trump's court losses, bringing up something never heard in any presidential debate, that Mr. Trump slept with a porn star and was found liable for molesting a woman. Both candidates describing what appear to be an alternative universe view of nearly every major voter concern. Galen Troop, they're partners at the political analysis site 538. On average, going back to 1976, the first debate has changed the polls by about two and a half percentage points.