Obama also works in some kudos for Clinton's vice presidential choice, Tim Kaine.
"Tim Kaine is as good a man, as humble and committed a public servant, as anyone I know. He will be a great vice president, and he’ll make Hillary a better president. Just like my dear friend and brother Joe Biden has made me a better president."
As Obama says, "And then there’s Donald Trump," the crowd boos.
He tells them, don't boo, vote!
The crowd cheers and laughs.
Another comment by Obama -- "Meanwhile, Donald Trump calls our military a disaster" -- draws boos from the delegates.
As Obama speaks, someone in the crowd yells, "Four more years!"