Psst, there is another debate on Tuesday.

No, not between Donald J. Trump and Hillary Clinton. They do not suit back up in their gladiatorial armor until next Sunday.

This one is between their running mates, Gov. Mike Pence of Indiana and Senator Tim Kaine of Virginia. Voters may be forgiven for barely knowing of it, or allotting it little space on their mental hard drives, because of the incendiary flashes tossed into the race daily from the top of the tickets, especially by Mr. Trump.

The meeting of Mr. Pence, a Republican, and Mr. Kaine, a Democrat, two pensive and little-known nominees, might be the least anticipated vice-presidential debate in 40 years.

“You’re essentially following Ali-Frazier a few days later with a nationally televised book club,” said Tucker Martin, a Republican strategist in Richmond, Va., about an hour from the campus of Longwood University, where the vice-presidential debate will take place.