Kamala Harris’s speech was the test of her political life. She passed, but there will be others – not least Gaza | Arwa Mahdawi

On 22 August 1964, a Black activist called Fannie Lou Hamer gave an iconic speech at the Democratic national convention (DNC), taking the party to task for its failure to support equal voting rights. Hamer did not get what she wanted that particular night in Atlantic City, but she helped pave the way for a new generation of American leaders.

On the 60th anniversary of that historic address, Kamala Harris stood centre stage at the DNC in Chicago as the Democratic party’s candidate for president and gave the most important speech of her life. The buildup to Thursday night was intense; Harris had been prepping furiously for this pivotal moment, reportedly workshopping her speech “ nearly line by line ”.

If the weight of history, and the pressure of the present, hung heavy on Harris’s shoulders she did not let it show. Ever since Joe Biden passed her the baton a month ago Harris has been a changed woman. Gone is the uncertain vice-president who didn’t seem quite at ease in her role. Gone is the often-awkward orator. Harris is in her element now and it shows. She’s spent the last month radiating joy. Electric and effervescent, she did not so much speak last night as sing.

While joy has been a major theme of the DNC, Harris’s speech made clear she wasn’t just about good vibes, she was ready to get to work. “OK, let’s get to business,” she said repeatedly as an exuberant crowd greeted her entrance with seemingly endless applause and chants of “USA”.

A key point of business? Unity. “I know there are people of various political views watching tonight,” she said looking directly at the camera. “And I want you to know: I promise to be a president for all Americans.”

To underscore this promise, Harris presented herself as a regular American whose modest upbringing, unlike Donald-silver-spoon-Trump, many could relate to. She started by speaking about her early life and her brilliant, trailblazing, immigrant mother, who “taught us to never complain about injustice, but do something about it”. She talked about growing up in the Bay Area of California in a “a beautiful working-class neighbourhood of firefighters, nurses, and construction workers”. And she spoke about how she decided to become a prosecutor to fight for the vulnerable after a high-school friend told her she was being sexually abused by her stepfather.

These stories weren’t just supposed to make Harris seem relatable, they were there to help her seem authentic. One of Harris’s biggest weaknesses when she unsuccessfully ran for the 2020 nomination was her inability to really define herself. Some critics called her a “cop” and a “bully”, others called her dangerously liberal. Back then, Harris didn’t seem entirely sure of what she stood for. Standing on the stage in Chicago on Thursday, however, Harris opened herself up. She owned her story.

While Harris may have begun by speaking about her past, the real focus of her acceptance speech was the US’s future. She thanked Biden gracefully but also signalled that he was now in the rear-view mirror. “We are not going back, and we are charting a new way forward, forward to a future with a strong and growing middle class … building that middle class will be a defining goal of my presidency,” she said.

Harris’s campaign hasn’t been very heavy on policy so far and this speech also stayed fairly surface-level. However this focus on the middle class echoed the populist economic policy agenda she previewed at a speech in North Carolina last week. In that speech she talked about bringing down the price of groceries, prescription drugs, and housing. Whether a Harris administration would actually be able to do all of this is up for debate, but it is certainly a message that resonates across all party lines .

The substance of Harris’s vision for the future, however, wasn’t so much about a cheaper loaf of bread as a safer democracy. The vice-president spoke bluntly about the threat a second Trump term holds. “In many ways, Donald Trump is an unserious man. But the consequences of putting Donald Trump back in the White House are extremely serious,” she said. “Consider the power he will have, especially after the United States supreme court just ruled that he would be immune from criminal prosecution.”

It was difficult not to consider, also, how much closer the US was to that terrifying possibility a month ago. With Biden at the helm, the Democratic party seemed on a course towards almost certain defeat. Now, while the race is still excruciatingly tight, the polls have turned in Harris’s favour. She has incredible momentum and, as her speech made very clear, she has what Biden sorely lacked: the energy to fight.

Nowhere was the contrast with Biden more apparent than when Harris spoke about reproductive rights. The nominee spoke stirringly about how she’d travelled across the US and heard stories of “women miscarrying in a parking lot, developing sepsis, losing the ability to ever again have children, all because doctors are afraid they may go to jail for caring for their patients”. God was it refreshing to hear her talk about abortion like she really cares. One of Biden’s many weaknesses was that he could never seem to stop his personal distaste for abortion from coming to the fore; he always seemed half-hearted. He could not channel the visceral anger emanating from American women.

“We’re not going back! We’re not going back!” That phrase, spoken by Harris, chanted by the crowd, rang through her speech. But despite the joy and the optimism it was difficult not to think back to Hamer’s speech. The activist, who was name-checked by the likes of Maxine Waters, member of the US House of Representatives for California, at the DNC, is celebrated by the establishment now, but when she was fighting for equality, she was reviled. During her testimony in 1964, then-president Lyndon B Johnson even called a news conference to try to divert attention from her; he was worried her speech would alienate white voters in the south from voting for Democrats. Today it’s clear that Palestinian-Americans, and people fighting for Palestinian rights, are similarly inconvenient to the Democratic party and its message of unity.

While Harris paid lip service to the crisis in Gaza and called for a ceasefire, what she said about the issue in her speech wasn’t as important as who was not given a speaking slot at the DNC. Despite pleas from pro-Palestinian members of the party, the Democrats failed to give a Palestinian-American a slot on the main stage. “No one should be made to fight alone,” Harris said in her speech. “We are all in this together.” They were stirring words – but it is hard to feel that we really are all in this together. Harris has laid out an invigorating vision for America’s future. It is a shame the DNC chose to leave Palestinian-Americans behind.

• Arwa Mahdawi is a Guardian columnist