 This is CBS News on the Hour, sponsored by O'Reilly Auto Parts. I'm Monica Ricks. Many undecided voters will be watching tonight's presidential debate between President Biden and former President Trump, like Lua Varner in Atlanta. Not a super huge fan of either, but just if they're respectful to each other, I feel like that's super important. That may prove difficult, though, considering these candidates have history. Here's CBS's Nancy Cordes.