PHILADELPHIA - Hillary Clinton needed support this week, everyone knew that. Her fellow Democrats attending the party’s national convention were going to have to make the case for her presidential run on her behalf. And one by one, they fulfilled their mission. Michelle Obama, Bernie Sanders, Bill Clinton – each played their role well.

But Barack Obama had a more difficult challenge. He had to provide a rationale for the millions of voters who remain unconvinced that she should be his successor. And there was more on his agenda Wednesday night at Wells Fargo Arena. He has a legacy to protect, too. And a certain Manhattan billionaire to cut down to size.

And his response was electrifying as he checked off the many boxes on his to-do list, including the reasons why he had to pass his baton to her.

“No matter how much people try to knock her down, she never ever quits,” Obama said. “There has never been a man or a woman, not me, not Bill, nobody, more qualified than Hillary Clinton to serve as president of the United States.”

And he didn’t pass on the opportunity to explain why Donald Trump must lose it.

“The Donald is not really a plans guy. He’s not a facts guy, either,” Obama said.  “The choice isn’t even close.”

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Obama was set up well by his tag-team partner, Vice President Joe Biden, who veered from the poignant to the profane in eviscerating Trump. Biden begged the crowd at one point to listen for a minute without booing while he performed surgery on Trump’s strong suits.

 “This guy doesn’t have a clue about the middle class,” Biden sneered. “He has no clue about what makes America great. Actually, he has no clue, period.”

It was raw meat for a hungry crowd. And it was followed by an unexpectedly effective balance-sheet dissection by former New York City Mayor Michael Bloomberg, one billionaire unmasking another.

Obama, a purveyor of hope and change, is at his best when he’s aspirational, and that was true again Wednesday night as he touched on familiar themes – the strength and resilience of America and Americans, the tough demands of democracy, and the necessity of compromise. And on that note, he had a message for Sanders’ supporters Clinton will need in November, telling them, “If you’re serious about democracy, you can’t afford to stay home because you don’t align with every issue.”

Obama also remembered their complicated history. They had a bitter primary fight in 2008, after which Clinton rallied her supporters behind him. In 2012, with Obama in trouble in his re-election bid, it was Bill Clinton who righted and energized Obama’s campaign with his superb convention speech. And in between, it was Hillary who served as his secretary of state.

“For four years, I had a front row seat to her intelligence, her judgment and her discipline,” Obama said.

When he was done, basking in the roar of a crowd that did not want to see him leave the stage, Clinton walked out, beaming. She knew what her former boss had just done for her. Obama enveloped her in a big hug, and a few moments later they walked off, partners in both the past and the future.