From a Wall Street Journal op-ed:

For days before the UN conclave, White House aides had broadcast the President’s desire to shake Mr Rouhani’s hand.  By Monday, the press was overflowing with leaked accounts of where and how it would happen.  Having thus turned down the lights and turned up the mood music, it made the snub that followed especially potent.

It would be amateur hour, if it weren’t so utterly incompetent.