If you were a candidate battling pneumonia and needed somebody to keep your campaign rolling, you couldn't do any better than calling on Barack Obama.

The president spoke for 40 minutes to several thousand supporters at the Eakins Oval in front of the Philadelphia Art Museum, and reminded us of what an impressive orator he is.

Yes, it was a friendly crowd, but the man knows how to connect — with tone, timing and message perfectly in sync.

(Clinton was never supposed to speak at this event, but her being sidelined from the campaign with illness somehow made Obama's super-surrogate act seem all that much more important.)

Philadelphia Democrats have given Obama warm receptions and huge electoral wins in his own presidential campaigns.

He was back asking for the same kind of effort for Clinton, and he said he wasn't just going through the motions, that he was seriously, personally committed to her.

Some find that surprising, he said, because they battled hard in 2008 for the Democratic nomination.

"It was tough, because Hillary's tough," Obama said. "Every time I thought I had that race won, I was going up those Rocky steps, I'd turn around, and she was right there. And I got whupped here in Pennsylvania. She whupped me."

High stakes, different election

Obama said this election amounts to a fundamental choice about who we are as a people, about the very meaning of America.

"This isn't Abraham Lincoln's Republican Party," Obama said of his opponents. "This is a dark, pessimistic vision of a country where we turn against each other. We turn away from the rest of the world. They're just fanning resentment and blame and anger."

He criticized Donald Trump, of course, but he also borrowed a trick from Trump's rallies, in which the candidate turns the crowd's attention to the press riser behind the audience.

"I sure do get frustrated with the way this campaign is covered," Obama said. "Guys in the back, I'm just telling you the truth about how I feel about this. Do you mind if I just vent for a second?"

That brought a roar of approval from the crowd.

Obama said nobody grades the presidency on a curve, but somehow Trump seems to escape the kind of scrutiny that others get.

"Donald Trump says stuff every day that used to be considered as disqualifying for being president," Obama said. "And yet, because he says it over and over and over again, the press just gives up and they say, 'well, yeah, OK.'"

Obama didn't address any of the controversies that have dogged Clinton during the campaign — her emails, the Clinton Foundation, her health, or her calling some Trump supporters "deplorables."
He did say when she joined his administration as secretary of state, he saw what she was made of.

"For four years, I had a front-row seat," he said. "I watched her intelligence. I watched her judgment. I watched her discipline. I saw her in the Situation Room where she argued for the mission for Bin Laden."

He called Clinton the most qualified person, woman or man, ever to seek the presidency, and urged the crowd to register their friends to vote and work hard for a win in November.

Obama's visit underscores the importance of Pennsylvania in the presidential contest. Just a few hours after his speech, Trump spoke at an event in Delaware County.