Washington: There was a point nearly an hour into his White House press conference championing the Iran nuclear deal when President Barack Obama clearly felt they had not asked him enough questions.
So the President held his ground, all but threatening to ask himself some of his own unless the press came up with some more.
"OK. I'm just going to look – I made some notes about many of the arguments – the other arguments that I've heard here," he said during a pause, treading water until another question lobbed in.
"OK, yeah, that's a good one," he said, diving into a response about the long-term implications of the deal.
It was an odd but telling moment for a president not known for enjoying the menial labour of selling his initiatives.
Where Mr Obama once was content to let his major policies speak for themselves – to the great dismay of those who sought to defend Obamacare during the bad old days – he appears determined that his administration will do all it can to shape the public understanding of the Iran deal.
"The bottom line is this: This nuclear deal meets the national security interests of the United States and our allies," he said before taking on criticisms point by point.
"It prevents the most serious threat – Iran obtaining a nuclear weapon, which would only make the other problems that Iran may cause even worse.
"Without a deal, the international sanctions regime will unravel, with little ability to reimpose them.
"With this deal, we have the possibility of peacefully resolving a major threat to regional and international security.
"Without a deal, we risk even more war in the Middle East, and other countries in the region would feel compelled to pursue their own nuclear programs, threatening a nuclear arms race in the most volatile region in the world."
Critics of the White House believe that in its transparent desire to come to a deal with Iran the administration too cheaply ceded the leverage the international negotiating parties had won by putting in place binding sanctions that were crippling the Iranian regime.
The White House believes that the sanctions stood no chance of holding if this deal failed. China, Russia and Europe would have folded and begun doing business again and the leverage would have been lost for no gain at all.
"What I haven't heard is: 'What's your alternative?'" Mr Obama asked rhetorically at one point. "Future generations will judge us harshly for letting this moment slip away."
In part Mr Obama's zeal in selling the deal is practical. Debate about will soon begin in Congress where Republicans will doubtless exploit their majorities in both houses to subject the deal to withering scrutiny.
But the Republicans cannot block the deal without a two-thirds majority, and they are not likely to win this, especially since Hillary Clinton has come out in favour of the deal. Most Democrats will rally around the President.
There is more at stake for the President. Flushed by a summer of culture war victories and policy success, Mr Obama is seeking to burnish his legacy.
He has made it clear that he considers reaching a diplomatic outcome with Tehran to be the crucial foreign policy achievement of his second term, more significant even than a successful negotiation of the Trans Pacific Partnership.
He is determined that it will be understood in his terms.
US prisoners not part of deal
Then he was confronted with an awkward question.
The CBS chief White House correspondent, Major Garrett, stood and asked Mr Obama about why American negotiators did not make the release of Americans - a Washington Post journalist, a former marine, a Christian pastor and a retired FBI agent - in Iranian captivity part of the negotiations.
"Can you tell the country, Sir, why you are content, with all the fanfare around this deal, to leave the conscience of this nation, the strength of this nation, unaccounted for in relation to these four Americans?"
At first the President appeared to be unruffled by the question, but as his answer went on it became clear how angered he was by it.
"I've got to give you credit, Major, for how you craft those questions," he began.
"The notion that I am content as I celebrate with American citizens languishing in Iranian jails, Major, that's nonsense, and you should know better.
"I've met with the families of some of those folks. Nobody's content. And our diplomats and our teams are working diligently to try to get them out."
