The smiles were a reflection of a successful summit.

The president of the United States.

But then from the host, with his final word, this.

And now I want to hand it over to the president of Ukraine, who has as much courage as he has determination. Ladies and gentlemen, President Putin. President Putin. He's going to beat President Putin. President Zelensky.

President Biden had blown it, it seemed, before the big screen test had even begun. The solo news conference, surely the most anticipated moment of his presidency, had been delayed and was now more make or break than ever. It did not start well.

I wouldn't have picked Vice President Trump to be vice president. I think she was not qualified to be president.

The questions came fast and awkward. George Clooney and a handful of lawmakers have called on you to step aside.

Have you spent time thinking about what it would mean for your legacy?

Hasn't this now, frankly, become damaging for America's standing in the world? Two weeks exactly since that debate disaster, and he was now facing it head on.

Only thing AIdS does is helping with it creates a little bit of wisdom if you pay attention. I've not had any of my european allies come up to me and say, joe, don't run. What I hear them say is, you've got to win.

The problem is that so many now on his own side, privately and more and more publicly say, he can't win. He won't win. He's not listening.

I believe I'm the best qualified to govern, and I think I'm the best qualified to win.

It was a doubling down.

Once again, with his top team, front.

Row, he stuck largely comfortably to foreign policy. A flurry of gaffes. It was not yet within it. A fresh awareness may be of a different direction should it become inevitable. Explicit praise for Vice President Harris.

She is qualified to be president. That's why I picked her.

If your team came back and showed you data that she would fare better against former President Donald Trump, would you reconsider your decision to stay in the race?

No. Unless they came back and said, there's no way you can win.

The thing is, many are saying precisely.

That, well, it feels like that was a performance that will only prolong this agony. It wasn't bad. It wasn't bad enough for definitive action, but neither was it good enough to end it all. For Donald Trump, this is good news. Biden is the vulnerable, beatable opponent he wants.

Mark Stone, Sky News in Washington.