Trump's 'adolescent' letter to Turkey stuns ex-White House adviser: 'It is unprecedented'
CNN Senior Political Analyst and former White House staffer David Gergen

On Wednesday's edition of CNN's "OutFront," David Gergen, a former White House adviser to four presidents, was astonished by President Donald Trump's letter to Turkish President Recep Tayyip Erdoğan warning him "don't be a fool."

"I don't want to laugh about it because it's — this is a letter that was actually sent, at least, he says it was," said host Erin Burnett. "Have you ever seen anything like this?"

"Well, Erin, many presidents write tough letters, nasty letters, angry letters, frustrated letters. The normal presidents then put them in a jar in a file called 'burn before sending,'" said Gergen. "This had such an adolescent quality to it when I read it, I immediately called my researcher, and I said, see if this is fake."

"I can't believe the White House sent this out, because it is unprecedented, to the best of my knowledge, and it makes it tougher to work with Turkey, which is a member of NATO, and we need to figure out ways to get this stopped, hopefully short of much more violence," said Gergen.

Watch below: