At tonight’s meeting of the Democratic National Convention, attendees have been treated to fiery speeches by Vice President Joe Biden, Vice Presidential nominee Tim Kaine, and former New York mayor Michael Bloomberg. As of this writing, President Obama is currently addressing the crowd.

Last night, former president Bill Clinton took the stage to vouch for his wife, and today he was prominently seated in the audience. Those watching him closely as he reacted to Biden’s speech quickly noticed something unusual:

As it turns out, the pin was a gift from either one of two political operatives associated with the National Jewish Democratic Council. Steve Rabinowitz of Bluelight Strategies, which represents the NJDC, and who formerly worked in the Clinton White House, explained to me what had happened:

I was at a Clinton/Gore campaign alumni event this afternoon at the National Museum of America Jewish History in Philadelphia and gave my old boss the pin. He said he’d wear it but I didn’t know whether or not to believe him and certainly didn’t think he’d do it tonight.

Meanwhile, separately and without either of us knowing it, Marc Stanley [the chairman of the National Jewish Democratic Council] did the same thing tonight when he saw Clinton in the convention hall and Clinton told him he was planning to wear it.

Don’t know who gets the credit but we’re both happy. It’s NJDC’s pin.

Perhaps Clinton intended the sartorial choice as a subtle rebuke to those former Bernie Sanders supporters who, after some walked out to protest Hillary Clinton’s nomination, burned an Israeli flag outside the convention. In his speech that night, Clinton had related a favorite anecdote about how Hillary implemented an early education reform based on an Israeli pre-K program she’d encountered. Meanwhile, the NJDC condemned the flag-burning outside as “disgusting,” “totally reprehensible,” and “anti-progressive.”

It seems reasonable to presume the Clintons agree.

Related: Tablet’s 2016 Democratic National Convention Coverage