The former president and once-again-future president, who are historically something less than besties, chatted it up before the service began. (Michelle Obama was not in attendance.)

Trump is obviously no fan of Biden, but Obama and his veep also have a famously complex relationship, only made more so after Obama helped nudge Biden to quit the presidential race last summer. Surely Obama feels some frustration that Biden fumbled a possibly winnable race; maybe he couldn’t help spill to his sworn enemy?

One of the first calls Obama made after U.S. forces killed Osama bin Laden in 2011 was to George W. Bush to spread the word that the mission had been accomplished, said Kate Andersen Brower, author of “Team of Five: The Presidents Club in the Age of Trump.”