In particular, he referred to their conversations after Biden lost his son Beau at the age of 46 in 2015 to glioblastoma.

“I was a friend, and sounding board, and counselor to him during that process, but he made the ultimate decision. And the same is true this time round,” he said.

Obama did acknowledge Biden’s “bumps” during the Democratic primary, a process throughout which he declined to endorse him. But he emphasized that his former lieutenant “came into his own during the general election.”

Obama also reflected on his own transition, as President Trump’s refusal to concede slows the Trump-Biden transfer of power. He admitted he “didn’t enjoy” calling Trump to congratulate him four years ago when he defeated 2016 Democratic standard-bearer Hillary Clinton.

Obama wrote in A Promised Land about riding to the United States Capitol Building for his 2008 inauguration with outgoing President George W. Bush. Gazing out the windows of the “Beast” limousine, Obama recalled seeing protesters lining Pennsylvania Avenue and remembered thinking it was “graceless and unnecessary.”

On Thursday, Obama didn’t say that he would feel the same way regarding protesters who might demonstrate against Trump on his way out of the White House.

“2008 is very different than 2020. The way Donald Trump’s behaving in transition is very different than the way George Bush behaved on his final months of when he was in office,” he said.

For Obama, he agreed with Biden, adding “we should all make an effort to do our best to lower the temperature, and listen to the other side.”

“But I think when you have a current president whose entire style is to fan division, that’s hard while he’s on the stage,” he continued.

Obama’s third book was launched on Tuesday. He sold roughly 890,000 copies in the first 24 hours of its release.