Barry Diller’s decision to pull the plug on a $250 million deal to rehab and create a new landmark along the Manhattan waterfront has taken even the lawyers by surprise.

“Quite frankly, I’m not clear as to the real causes of his decision,” said Richard Emery, a founding partner of Emery Celli Brinckerhoff & Abady, who represented the City Club of New York, which had been opposed to the project.