US President Barack Obama has put his whole weight behind Democratic presidential nominee Hillary Clinton with a powerful speech, calling her the most qualified person to lead the nation.
"I can say with confidence there has never been a man or woman, not me, not Bill [Clinton], not nobody, more qualified than Hillary Clinton to serve as president of the United States of America," he said at the Democratic National Convention.
Mr Obama had previously battled Ms Clinton for the Democratic nomination in 2008, a rivalry he describes as "tough".
"Let me tell you it was tough, because Hillary was tough," he says.
"No matter how much people try to knock her down, she never, ever quits! That is the Hilary I know."
National unity was a key focus in Mr Obama's speech, stressing to the crowd that democracy would only be effective if everyone participated.
"Democracy isn't a spectator sport. America isn't about 'Yes he will' - it's about 'Yes we can'," he said to loud cheers
"And we're going to carry Hillary to victory this fall because that's what this moment demands.
"'Yes, we can'. Not 'Yes she can', not 'Yes I can', 'Yes we can'."
It was one of the things Mr Obama attacked Republican nominee Donald Trump on.
"America is already great. And I promise you our strength, our greatness, doesn't depend on Trump. It doesn't depend on any one person," Mr Obama said.
"America has never been about what one person can do for us, but what we can achieve together.
Mr Obama's mentions of Mr Trump drew loud boos from the crowd, to which he replied: "Don't boo - vote!"
Mr Trump had previously dismissed the US military as a "disaster", something Mr Obama took offense to in his speech.
"I know Hillary won't relent till [Islamic State] is destroyed - she will do the job. And she will do it without resorting to torture, and banning entire religions.
"[Mr Trump]'s betting that if he scares enough people he might score just enough votes to win this election. And that's another bet Donald Trump will lose."
It's important everyone overlooks the darkness that has covered the nation, Mr Obama says, and to keep faith.
"So this year in this election I'm asking you to join me and reject cynicism and reject fear, and join me and elect Hillary Clinton as the next president of the United States!" Mr Obama said.
Mr Obama received a standing ovation from the attendees at the convention.