George W. Bush gave fellow former president Barack Obama a friendly belly tap at the Jan. 9 funeral of Jimmy Carter, and the internet was obsessed with the viral moment.

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.”