In her speech at La Salle University in North Philadelphia on Wednesday, Michelle Obama did not refer to Donald Trump by name. This is evidently family policy, decided on at a White House strategy session or around the dinner table.

“If a candidate is erratic and threatening, if a candidate traffics in prejudice, fears and lies on the campaign trail… if a candidate regularly and flippantly makes cruel and insulting comments about women, well sadly, that’s who that candidate really is,” she said.

The First Lady’s stump speech is familiar by now. She touted her husband’s record, described the awesome responsibilities of the presidency, ticked off Hillary Clinton’s qualifications for the job and invoked a tolerant, surely-we’re-better-than-this United States of America, before closing with a direct appeal. “Let’s be clear,” she told the students. “Elections are not just about who votes, but who doesn’t vote.”

Barack Obama won Pennsylvania handily in both his presidential campaigns, but the state is becoming more Republican with each electoral cycle. In 2012, Mitt Romney won 55% of the vote outside of greater Philadelphia, but still lost by more than 300,000 votes because Obama’s margins were overwhelming in the city and the suburbs.

Around 44% of Philly’s voters are African-American. Record black turnout allied to 99% support for Obama bolstered his 490,000 vote cushion here. Wednesday’s appearance by the First Lady, the Democratic Party’s most popular figure, was an acknowledgement that it will be tighter this time. If Obama’s urban coalition is less motivated to elect his successor, Clinton could well lose the state.

The National Action Network’s Philadelphia headquarters is a dreary basement in a red brick council house on West Jefferson Street. On evenings and weekends, volunteers gather here to pick up voter registration packets and go canvassing, but when I visited, after Michelle Obama’s speech, the seventy-three-year-old chapter president, Matthew Smith, had the place to himself.

“I don’t think the African-American turnout will be as great for Secretary Clinton as it was for President Obama, but there will be enormous support,” he said. “People are beginning to look and ‘oh my God, this is who we might be getting for president if we’re not careful’.”

Smith is a faithful servant of the Democratic Party machine, born in the South, raised in the church and forged by the Civil Rights movement. As a student at Benedict College in South Carolina he risked his life on the picket line and at the whites-only Woolworths lunch counter. “They would have the fire hoses ready, the dogs and the guns pointed on us,” he said. “Segregation was always there. We came to realise later that it never died.”

Sometimes, the young people that he speaks to wonder if he is “telling them fairytales” about the past. Many say that direct action is the only way to effect change and that they don’t intend to vote. “The difference is, when I was coming up, we were just being able to vote without possibly getting killed. To me, voting is a sacred thing,” Smith tells them.

At a rally in Kenansville, North Carolina last month, Donald Trump made a rare - and dreadfully conducted - attempt to court black voters. “Our African-American communities are absolutely in the worst shape they've ever been in,” he claimed. ”You take a look at the inner cities, you get no education, you get no jobs, you get shot walking down the street.”

“I say this to the African-American communities, and I think it's resonating,” he continued, “because you see what's happening with my poll numbers with African-Americans. They're going, like, high.” In fact, he has consistently polled in single digits and occasionally at zero among black voters.

Obama won 95% of the African-American vote in 2008 and 93% in his re-election campaign. Clinton may well post similar numbers. The key question is whether turnout will remain high without the first black president on the ballot. In 1996, 53% of eligible African-Americans voted. By 2012, the participation rate had surged to 66%, surpassing that of whites for the first time.

Black voters could tip the balance in Florida, Michigan, North Carolina, Ohio, Virginia and Pennsylvania. At the Congressional Black Caucus Foundation dinner, Obama said he would consider it a “personal insult” if African-Americans don’t show up for Clinton.

The streets of North Philadelphia are brightened by murals every few blocks, many of them honouring civil rights icons. There are signs of gentrification - new apartment blocks built for outsiders, by outsiders - but the rows of boarded up townhouses, the vacant lots and the weeds growing through cracks in the playground tell a depressingly familiar story of urban neglect.

A poem written on a school wall on North College Avenue urges “Don’t Pick The Wrong Fight.” Posters plastered in shop windows by Philadelphia Ceasefire put it bluntly: “Stop. Shooting. People.” According to the latest census data, 57% of North Philadelphia families live below the poverty line. Citywide, around 186,000 people live in deep poverty - defined as an annual income of less than $12,000 for a family of four.

Kevin Horne was waiting for me by his food truck, Horne’s Famous Foods, on the Drexel University Hospital campus. The family business, started by his grandfather in 1931, has expanded to become a fleet of four mobile canteens, parked at popular lunch spots. As we talked, his son worked the counter behind us.

A veteran community organiser, Horne leads Southwest Philadelphia District Services, an NGO that provides affordable housing and job training in another of the city’s poorest neighbourhoods. He grabbed two folding chairs and set out to convince me that Clinton cannot take the black vote for granted, punctuating his observations with “hear this” and “get this right,” as if tired of being misrepresented.

“I can go for Clinton or I can go for Trump. Either one of them has showed the Afro-American community nothing,” he began. He said he would make up his mind based on which candidate visits black neighbourhoods and outlines a detailed plan to improve them over the next few weeks.

Horne scoffed at the suggestion that Clinton has done this many times during the election campaign, not to mention the last thirty years. “She has deep ties with the Democratic machine,” he said. “But no pastor or politician can tell me who to vote for, because that’s the business as usual that’s been happening in our neighbourhood. The schools are run-down, crime is up, drugs are popular. Philadelphia - the Democrats have been dominant for so long. Look at the mess we're in.”

Most people in your neighbourhood will vote for Clinton, I venture. White Democratic nominees Al Gore and John Kerry both won 98% of Philadelphia’s African-American vote. “Maybe that’s true,” Horne allowed. “In the Afro-American community, I see Clinton has the edge.”

She needs more than the edge. She needs overwhelming support. “She’s not gonna get that,” Horne said, flatly. “Half the people at my meeting’s are going to vote for Donald Trump. I tell you that right now.”

At Monday night’s debate, Clinton often seemed to be talking directly to African-American voters. In unusually strong terms, she denounced the “racist lie” disseminated by Trump that President Obama was not born in the USA, and referred to “systemic racism” and “implicit bias,” not only in the criminal justice system but society as a whole.

Trump, in contrast, promised to implement the New York Police Department’s former policy of “stop and frisk” nationwide, even though it was ruled unconstitutional by a federal court because it discriminated against minorities. Did none of this sway Horne? What about Trump’s supporters in the Ku Klux Klan and the American Nazi Party? “I can’t be scared off by racism, because I lived in a community where that’s all we saw, from president to president,” he said.

One in four eligible African-American voters is under thirty-five years old. Clinton is perceived to have particular difficulty connecting with this demographic, although polling data is scarce: a GenForward survey in August showed her winning 60% among black millennials. Only 2% said they would vote for Trump. The rest planned to vote for a third party candidate or not at all.

Black Lives Matter activists are wary of Clinton due to her support for criminal justice legislation passed during her husband’s presidency that resulted in millions of African-Americans being given longer sentences for lesser crimes. Trump seeks to exploit this distrust. In the debate, he alluded to a comment Clinton made in 1996, describing gang members as “super-predators” that needed to be “brought to heel”.

Clinton has apologised for the remark, and made efforts to court young activists by sharing a stage with the mothers of unarmed black men killed by police. Sharif Street, a Democratic candidate for Pennsylvania’s state senate, suggested that the protests against police brutality are a net positive for her. “Black Lives Matter brought new people into the system. They believe direct action is more effective than voting, but I think most of them will vote,” he said.

At the Clinton campaign office on Cecil B. Moore Avenue, senior citizens Antoinette Gooding and Lolita Tull were settling in for an afternoon on the phones, asking people on the party list to register, vote and volunteer. Tull had come from Dunkin’ Donuts, where she had tried and failed to convince the young man making her coffee that his vote matters.

“We have a lot more of the millennials who are eligible to vote, and when you talk to them about the importance of voting, some say ‘well, I’m not going to vote because blah, blah.’” She threw up a hand in frustration. “I don’t know how you change their mindset. I can’t seem to fathom that.”

Trump will win Pennsylvania if turnout is low in Philadelphia, I said. “I know that. I believe that,” she sighed. “We’re pushing hard, but the millennials, and not only the millennials, you have older voters that are just sick of government. They don’t believe in politics. They feel like whoever wins it’s going to be the same old same old, which is ridiculous.”

Outside, Puerto Rican barber Gilberto Albizu was sat at a table, asking passers-by if they were registered. “I've seen a lot of people that are willing to do more, in my opinion, because Mr Trump is a disgrace,” he said.

This appears to be the Democratic Party’s main hope, in Philadelphia at least. Sharif Street, whose father John was the city’s first black mayor, admitted that “a lot of people feel let down by Democratic politics in a generic way… However, that normal apathy will be mitigated by people who say ‘the Democrats could do more, but Donald Trump is crazy.’

“The word I hear most from people is ‘I’m scared’ - that he could be president. People are scared. And negative energy is energy nonetheless. I feel like it ultimately will manifest itself in people going to vote. Even if they’re not voting for the candidate they most love, they’re voting against the candidate they most fear.”

This is a risky assumption in a segregated city where downtown is thriving but one third of the population survives on food stamps. Half a century’s worth of Democratic mayors have failed to address chronic underinvestment in African-American communities. In his eight years in office, the nation’s first black president has done little better.

Kevin Horne described schools where there are “no books, no hand towels in the recreation centre, no toilet tissue, not a decent mop.” He voted for Obama twice, Bill Clinton too, but is leaning towards Trump this time. “I’m not caught up in the scare tactics of ‘Donald’s coming’ and I’m not a believer that Hillary Clinton is going to save the day,” he said. “This is not a cartoon: this is real.”