The vice presidential candidates head to Longwood University in Virginia, Tuesday night,  for their only debate this election cycle. 

How Republican Mike Pence and Democrat Tim Kaine perform may offer a glimpse into how they'll approach being in office. But what makes a good vice president, and how has the role changed over the years?

To answer the questions, Take Two spoke with Rachel Van Sickle-Ward, a political scientist at Pitzer College. 

To hear the full conversation, click the blue player above