The Democratic Party has started pulling out the big guns in the race for the White House, as President Barack Obama personally implored voters Tuesday in Philadelphia to get out there and campaign to help Hillary Clinton win. 

A crowd of thousands packed Eakins Oval by the Art Museum to hear Obama confront some of the most common criticism and attacks that have dogged Clinton and blame the media for judging her more harshly than her opponent Donald Trump. 

"She's been accused of everything you can imagine, and has been subjected to more scrutiny and what I believe is more unfair criticism, than anybody out here," Obama told the crowd, to cheers.

"I sure do get frustrated with the way this campaign gets covered. Do you mind if I just vent for a second?" 

Obama went on to compare the most common criticisms of Clinton—her transparency, her private email server, and the Clinton Foundation's activities—to the criticisms of Trump. He pointed out that Trump hasn't released any of his personal tax returns.

"One candidate's family foundation has saved countless lives around the world," Obama said his former secretary of state and 2008 rival for the Democratic presidential nomination. "The other candidate's foundation took money other people gave to his charity and then bought a six-foot-tall painting of himself."

As the crowd roared with laughter, Obama comically added, "At least he had the taste not to go for the 10-foot version."

But Clinton's polls numbers may be slipping as her strong lead coming out of the Democratic National Convention has begun to erode. A new Quinnipiac poll released last week found Clinton with a five-point lead in the battleground state of Pennsylvania, half of what she had a month ago. Polls show a dead heat in Florida between the two candidates.

Meanwhile, the Washington Post reported that Democratic voters in the state aren't very enthusiastic, that African American voters are "lukewarm" and won't just vote to defeat Trump, and that low turnout is expected, which could hurt Clinton.

Obama's visit, which shut down roads through Center City and snarled traffic all day, was likely planned to keep the campaign's energy up. Bernie Sanders is scheduled to campaign for Clinton at Carnegie Mellon University in Pittsburgh on Friday.

"My most important message is we cannot take this election for granted," Obama told the crowd. "We've got to fight for this thing... We can't afford to have someone treat this like a reality show."

Pipeline protesters show up

The president's appearance attracted protesters—in this case, people who oppose a new oil pipeline being set up near Standing Rock reservation in North Dakota (known as the Dakota Access Pipeline or DAPL). The Obama administration recently halted the project, but that's not enough, protesters said.

"They stopped it temporarily, but it's not permanent," said protester Claudia Crane, 65, of Philadelphia. "A lot of us here oppose all pipelines. ... Poor, indigenous people get exploited first, but we're all going to suffer."