If Joe Biden wanted to make a few gaffes to do the most damage to his presidency, it would be hard to do better than his performance on Thursday night.
This NATO summit in Washington has already been overshadowed by questions about the age and mental capacity of the American president. In interviews here, all world leaders have been asked about this.
Two miles away, on Capitol Hill, Democrats have been meeting in conclave all week to discuss what to do about Biden and his health.
All eyes were on this evening, to see if he could close this summit without any problems. He couldn't.
There were muffled screams in the media center, where hundreds of journalists had gathered to watch the press conference.
On screens in the room, Biden turned to the left and prepared to make way for Zelensky.
“And now I want to hand over the baton to the President of Ukraine, who has equal amounts of courage and determination,” he said.
He paused for effect and concluded: “Ladies and gentlemen – President Putin.”
The atmosphere among the journalists present immediately changed from curiosity to horror.
The feeling in the room was exactly the same as at the June 27 presidential debate, when Biden froze on stage. People looked at each other as if to say, “Can this really happen?”
Minutes later, Sir Keir Starmer, Olaf Scholz and Emmanuel Macron were asked about it in their own press conferences and they all dismissed Biden's mistake as an innocent slip of the tongue.
But the truth is, the timing of this incident couldn't have been more unfortunate.
But an hour and a half later, he did it again. In his own press conference, Biden was asked about Kamala Harris’s fitness to be president, in an apparent nod to the idea that she would replace him on the Democratic ticket.
“I would not have chosen Vice President Trump as vice president if she was not qualified to be president,” he said. More sighs as the penny dropped that he had mistaken his closest ally for his greatest enemy.
Biden struggled as he explained that the NATO press conference was the most successful in “a long time” and that other world leaders credited him with bringing them together.
His own speech was unusual for a world summit, focusing on the differences in his foreign and domestic policies with Trump's.
At one point he started talking about US inflation rates ─ putting himself into full campaign mode ─ in an attempt to gain an attack on his own mistake. He said Trump was a threat to the NATO alliance.
I don't think this will be enough.
With his campaign facing unprecedented pressure from his fellow party members, Biden's team is hoping this week's summit will be an opportunity to showcase his “big boy” credentials.
He was supposed to show up and play his favorite role: the man who saves the world from Russia and prevents a second term of what he calls Donald Trump's “insane” agenda.
Instead, he turned America into an international joke, sending Western leaders scrambling to defend him.
It is almost certain that there will be more Democrats tonight who declare they can no longer support his campaign.
If Biden looked shaky at the beginning of this week, it seemed like he was done for tonight.
Broaden your horizons with award-winning British journalism. Try The Telegraph free for 3 months with unlimited access to our award-winning website, exclusive app, money-saving offers and more.
