Meet the moderators for the VP debate, Norah O'Donnell and Margaret Brennan

The vice presidential debate between Ohio Sen. JD Vance and Minnesota Gov. Tim Walz on Tuesday night, hosted by CBS News in New York, was the first and only meeting between the two vice presidential candidates. It comes as voters in several states have begun receiving their ballots for November's election.

The debate was moderated by "CBS Evening News" anchor and managing editor Norah O'Donnell and "Face the Nation" moderator and chief foreign affairs correspondent Margaret Brennan. 

There was no studio audience for the debate, and only O'Donnell and Brennan asked the questions. Here's what to know about the moderators and how they prepared for the event: