The backstory behind the pin Tim Kaine was wearing at the vice presidential debate

Viewers tuning into Tuesday's vice presidential debate appeared to have a question on their mind: What pin was Virginia Sen. Tim Kaine wearing?

According to Google, searches for "Kaine pin" spiked as the debate started.

So what pin was he wearing? The Democratic vice presidential nominee had on a Blue Star Pin, which is worn by family members to represent deployed military personnel.

Kaine's son is an active-duty member of the Marine Corps, something he noted in his opening remarks at Tuesday night's debate against Indiana Gov. Mike Pence.