1. Obama’s memoir contains revealing insights—and useful lessons—about his Iran policy. Perhaps the central takeaway was his understandable concern that conflict with Iran could “upend” his entire presidency, just as the Iraq war upended George W Bush’s presidency.

2. Obama writes that weeks into his presidency he wrote a secret letter to Iran’s Supreme Leader in the hopes of commencing US-Iran dialogue. Khamenei’s harsh response, Obama said, was tantamount to “the middle finger.”

3. Months later, in June 2009, huge protests erupted in Iran. Obama says after seeing the gruesome murder of Neda Agha-Soltan he wanted to express “strong support” for the demonstrators, but was dissuaded from doing so by his advisors, who believed US support would “backfire.”

4. After his initial efforts to engage Iran failed, Obama changed tactics and began a multilateral pressure campaign to force Tehran to curtail its nuclear program. Given his unreciprocated attempts at diplomacy, European allies, Russia, and China supported this tougher approach.

5. Getting Iran policy right is very difficult; Obama’s memoir was a reminder that the lone policy that’s worked over the last four decades is the combination of pressure and diplomacy. Obama initially tried only the latter and failed, and Trump tried only the former and failed.