“Among the people who called to thank me was President Obama,” McCain writes in his upcoming book The Restless Wave. The book is due out on May 22, but The Daily Beast obtained an early copy.

McCain and Obama had run against each other for the presidency in 2008. But over time, they had re-established a solid working relationship. Both share a healthy skepticism of the current president, a point the senator appeared to underscore later in the book.

“I appreciated his call, but, as I said, my purpose hadn’t been to preserve his signature accomplishment but to insist on a better alternative, and to give the Senate an opportunity to work together to find one,” the Arizona Republican writes. “He hadn’t called to lobby me before the vote, which I had appreciated. He had last called me not long after the November election, during the transition to the Trump administration, to congratulate me on my re-election. He added that he was counting on me to be an outspoken and independent voice for the causes I believed in as I had been during his presidency. I thanked him, and said I would try to be.”