Last week, Donald Trump and Hillary Clinton set viewership records for a presidential debate, with 84 million people tuning in.

Tuesday's 9 p.m. ET showdown between vice presidential candidates Mike Pence (the Republican) and Tim Kaine (the Democrat) is unlikely to challenge that record. Unlike last week, the debate is not competing with an NFL football game, but Tuesday is the first day of the Major League Baseball playoffs. (Baltimore Orioles vs. Toronto Blue Jays; first pitch scheduled for 8:08 p.m. on TBS, in the event you want to catch a couple of innings before switching to the debate.)

The format of the debate will be about the same as the presidential debate, but unlike last week's event, Kaine and Pence are not really the people voters are looking to hear from.

Instead, it is likely both of them will have to spend time explaining the controversial positions taken by their running mates. Mr. Pence, what do you make of Donald Trump's pre-dawn tweets about a former Miss Universe? Mr. Kaine, shouldn't the American public be concerned that Hillary Clinton mishandled classified information over email?

Here are a few things to keep in mind about the debate.