President Obama arrives to speak at a campaign event for Hillary Clinton on Thursday in Cleveland. Obama warned the “democracy itself” is on the ballot for the Nov. 8 general election. (Jim Watson/AFP/Getty Images)

In the spring, Ohio Democratic Party Chairman David Pepper went to White House officials with a request: He wanted President Obama to visit his state in the final weeks of the 2016 campaign.

Obama delivered for Pepper when he unleashed a full-throated attack on Republican presidential nominee Donald Trump and his party in Cleveland and Columbus on Thursday and Friday. Detailing the litany of conspiracy theories that critics have attached to his presidency, Obama blamed Republicans for creating Trump. “If your only agenda is either negative — negative is a euphemism, crazy — based on lies, based on hoaxes, this is the nominee you get. You make him possible,” Obama said during the state party’s annual dinner in Columbus.

“So don’t act like this started with Donald Trump. He did take it to a whole new level. I got to give him credit,” he said. “But he didn’t come out of nowhere. And that’s why we’ve got to win this election at every level.”

The question now facing Democrats is whether the president can energize enough of his supporters to overcome Trump’s appeal in one of the Rust Belt states the businessman is best positioned to win this year. While Trump’s lead over Democratic nominee Hillary Clinton here has shrunk and his campaign has faced problems — it cut ties with state GOP chairman Matt Borges on Saturday over perceived criticism — Ohio remains a toss-up. An NBC-Wall Street Journal-Marist poll released Thursday gave Trump a one-point edge.

“The way we win Ohio, we have to reconstitute the Obama coalition,” Pepper said in an interview, adding that the president’s “personal presence makes an enormous difference.”

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Obama’s two stops here were aimed at boosting turnout among millennials and African Americans. Those groups were critical to the president’s victories in Ohio in 2008 and 2012.

But as Trump has made inroads among the white, working-class voters, young voters, African Americans and women have become even more pivotal to Democratic prospects this year.

Nationally, Clinton remains much less popular with millennials compared with Obama, and trails him by a smaller margin when it comes to black voters. Sixty-six percent of registered voters under 30 surveyed in a late-September Washington Post-ABC poll said they approve of the president, compared with just 35 percent who declared the same of Clinton. Among African Americans, Obama won a 91 percent approval rating, compared with Clinton’s 83 percent.

On the campus of Case Western Reserve University, the challenge Clinton faces among young voters is clear. Three seniors, sitting at a table at the university’s student center, said they were unenthusiastic about backing the Democratic nominee despite their distaste for Trump.

Gabriel Murcia, 21, volunteered for Obama’s reelection campaign as a high-school student in Lancaster, Pa.

“I was on the Obama train back in the day,” he said, adding that while Trump “is pretty awful,” it sometimes prevents people from looking “critically at the way [Clinton’s] policies have negatively affected people of color both here and abroad, working people and LGBTQ people.”

Murcia plans on voting next month, at least so he can weigh in on local races. “But in terms of the presidential election, whether I can find it in my conscience to vote for Hillary, I don’t know.”

President Obama speaks at a campaign event in support of Democratic presidential nominee Hillary Clinton on Friday in Cleveland. (Phil Long/AP)

Libertarian Party candidate Gary Johnson has gained some traction in Ohio — he garnered 9 percent of the vote in Thursday’s NBC-WSJ-Marist poll — while Green Party candidate Jill Stein has been siphoning off a smaller share of the state’s electorate as well.

Johnson has won the backing of Blair Pitcairn, who makes ice cream at a local company and came to Obama’s rally on Friday at Cleveland’s Burke Lakefront Airport.

“I don’t think I’m swayed to vote for Hillary, but I’m more open to thinking she’ll be a better president than I thought,” the 25-year-old said, adding he prefers Johnson’s less interventionist foreign policy and his push for marijuana legalization as well as criminal justice reform.

But the Clinton campaign did manage to get plenty of recruits during Obama’s swing: At the Cleveland rally, staffers asked everyone when they filled out their ticket if they wanted to volunteer.

Alethea Smylie, a resident of Mayfield Heights, said she had come “primarily to see Obama,” although she planned to vote for Clinton. She said she was “unsure” about volunteering for Clinton but added Obama did make her “consider it a little more.”

Democratic Party officials said they are confident they have developed the infrastructure on the ground to edge out Trump even if his supporters appear more enthusiastic. Trump has a less robust field operation than Clinton, but he has drawn much larger crowds than her during his repeated visits here.

“Whether someone likes someone or loves someone, as long as they’re gotten to the polls, a vote is a vote is vote,” said P.G. Sittenfeld, a Cincinnati City Council member who ran unsuccessfully for the Democratic nomination for the Senate this year.

“Hillary Clinton has had her hands on all of the bad trade deals over the last 23 years that have sent Ohio jobs overseas and has a hard time hiding her disdain for regular working Americans,” said Trump’s Ohio communications director, Seth Unger. “Mr. Trump’s ‘America First’ message is resonating across Ohio.”

Obama, for his part, urged the 2,500-person audience standing on the shore of Lake Erie on Friday to head to the polls as soon as his rally ended.

“And I know everybody here is early voting, because otherwise you wouldn’t be here,” the president said. “If you stood in line to get in this rally, then you got enough sense to go early-vote.

“Donald Trump’s closing argument is ‘What do you have to lose?’ The answer is: Everything,” he told the audience standing in the sunshine on the shores of Lake Erie. “All the progress we’ve made right now is on the ballot.”

Emily Guskin in Washington contributed to this report.