Former U.S. President Barack Obama | Andreas Solaro/AFP via Getty Images Obama: Not bombing Syria ‘required the most political courage’ US military controversially didn’t intervene after Bashar al-Assad used chemical weapons on his own people.

Barack Obama defended his decision not to bomb Syria as president in an interview published Monday, casting his controversial decision as an act that “required the most political courage.”

Obama spoke with Jack Schlossberg last week before accepting a John F. Kennedy Profile in Courage award. Schlossberg, Kennedy’s grandson and a member of the award committee, released a transcript of their conversation in a Medium post Monday.

Sending troops into harm’s way was “the hardest issue that I dealt with,” Obama said, adding that seeing and knowing people younger than Schlossberg, 24, “would be in a really dangerous situation, that was tough.”

“But I actually think that the issue that required the most political courage was the decision not to bomb Syria after the chemical weapons use had been publicized and rather to negotiate them removing chemical weapons from Syria,” Obama said.

The Obama administration drew a so-called “red line” with respect to Syrian dictator Bashar Assad’s regime using chemical weapons on its people, arguing in August 2012 that the use of chemical weapons would provoke a military response from the U.S.

But Obama’s military never intervened after Assad used chemical weapons on his people. The administration instead continued pursuing a diplomatic resolution.

Obama said his approach, in retrospect, “was an imperfect solution” because while “99 percent of huge chemical weapons stockpiled were removed without us having to fire a shot,” the U.S. knows that some weapons remained in the Syrian regime’s possession.

“The reason it was hard was because, as president, what you discover is that you generally get praised for taking military action, and you’re often criticized for not doing so,” Obama said.

President Donald Trump, Obama’s successor, was widely commended for launching a retaliatory missile strike in Syria after Assad again used chemical weapons on his people. The president in a statement last month called the Assad regime’s “heinous actions … a consequence of the past administration’s weakness and irresolution.”

“It wasn’t a slam dunk,” Obama said of his own decision, “but I thought it made sense for a variety of reasons for us to see if could actually try to eliminate the prospect of large-scale chemical weapons than the political expedience of a one-time shot.”