“He’s used to getting what he wants and he’s a tough street guy,” said Billy Procida, a former vice president for the Trump Organization. “He’s been dealing with subcontractors his whole life. You know what it’s like to deal with subcontractors? They’re all terrorists. They all want more money for the job and then you’ve got to fight them and say, ‘OK, quid pro quo, I’m going to give you this, you do that, I’ll give you this, you do that, if you don’t do this, I’m going to do that.’”

The disjuncture between the table-pounding imperatives of New York real estate and the delicacies of international diplomacy helps explain, these people say, why Trump is having trouble understanding why his “perfect” phone call with Volodymyr Zelensky, the president of Ukraine, may have crossed a line.

“He does nothing without a quid pro quo,” said a former White House official. “Nothing. Whatever deal has got to be to his advantage.”

“He treats a lot of conversations and a lot of negotiations, including with foreign leaders, along those lines,” said another former White House official. “‘What is it that you want? Here’s what we want.’ How can we find a way to reach some kind of deal or accommodation where we both get what we want but in particular where I, representing the U.S., get what I want.”