On Tuesday, the Democratic and Republican nominees for vice president will face each other in their first and only debate. Historian Kate Andersen Brower says that, even though Minnesota Governor Tim Walz and Ohio Senator JD Vance both hail from the heartland, viewers should not expect "Midwestern Nice" to play out between the two. CBS News chief election & campaign correspondent Robert Costa looks at the history of VP debates. [CBS News will host the only planned vice presidential debate between Governor Tim Walz and Senator JD Vance on Tuesday, Oct. 1, at 9 p.m. ET on CBS and CBS News 24/7. Download the free CBS News app for live coverage, post-debate analysis, comprehensive fact checks and more.]