President Joe Biden’s opinion about how he withdrew troops from Afghanistan is that he “didn’t believe anyone had made a mistake,” according to an excerpt from a yet-to-be-released book.

Biden’s presidential foreign policy will be documented in a new book by reporter Alexander Ward. Among the milestones discussed will be the president’s decision to withdraw troops from Afghanistan in 2021, a move that came after an over 20-year war that resulted in 2,400 U.S. soldiers killed and 20,000 injured. During the withdrawal, an additional 13 service members were killed in a suicide bombing at the airport in Kabul. Ward shared an excerpt from the book, titled The Internationalists: The Fight to Restore Foreign Policy After Trump, with Axios.