From its opening moments, Vice President Kamala Harris’ acceptance speech made clear that no issue will shape the 2024 presidential election so much as voter attitudes toward America’s rapidly changing face.

In the nine years since he plunged into electoral politics, former President Trump has embraced nativism and made suspicion of immigrants central to his political brand.

He has made a call for “mass deportations” a key element of the current campaign. At his darkest, he has accused immigrants of “poisoning the blood of our country,” and he has forged his political movement around rejection of the demographic revolution that has reshaped the country over the past three decades.

Harris, a product of that revolution, embraced it in accepting her party’s nomination.

She described herself as a child of the American middle class, recounting growing up in Oakland in “a beautiful working-class neighborhood” located “in the flats,” not the hills.

The description drew a sharp contrast with Trump’s childhood of wealth. Even more starkly, however, her origin story contrasted with the vision of America that Trump has espoused.

Harris stressed her identity as the child of two immigrants — something that has not been true of an American president since the early 19th century — opening her speech with her mother’s “unlikely journey” from India to America, where she met and fell in love with a man from Jamaica.

As Harris continued, she placed the immigrant drive for success at the core of her presidential bid, accepting the nomination, “on behalf of Americans like the people I grew up with, people who work hard, chase their dreams and look out for one another … whose story could only be written in the greatest nation on Earth.”

That embrace of her immigrant background was one of two signature elements of Thursday’s speech. The other came with how Harris cast her relationship to the incumbent administration.

Over the course of the convention week, speakers used two very different metaphors to describe that relationship — passing the torch vs. turning the page.

The torch metaphor, a favorite of Democrats ever since John F. Kennedy’s inaugural address, cast Harris as the next in line, carrying forth President Biden’s policies.

That image has helped Harris unify Democrats over the last month, avoiding the divisions which might have followed the unprecedented effort by party leaders to push Biden into giving up his reelection bid.

By contrast, the “turn the page” metaphor, taken at its broadest, implies that the entirety of the last eight years — Biden’s term as well as Trump’s — constituted a troubled era from which the country can now move on.

Former First Lady Michelle Obama implied as much in her speech Tuesday night. She cast Harris as the heir to her husband as she extolled “the contagious power of hope. The anticipation, the energy, the exhilaration of once again being on the cusp of a brighter day.”

In her own speech, Harris, too, deployed that trope.

“With this election,” she declared, “our nation has a precious, fleeting opportunity to move past the bitterness, cynicism and divisive battles of the past — a chance to chart a new way forward.”

Despite that metaphor of a new day, large parts of the speech’s substance could have been delivered by Biden had he stayed in the race.

Harris drew battle lines on economic policy, pledging a middle-class tax cut while warning that Trump would reduce taxes “for himself and his billionaire friends.”

She depicted the across-the-board tariffs Trump has proposed as a “national sales tax” that would raise costs for everyday goods.

She painted stark differences on foreign policy, where she pledged support for Ukraine and accused Trump of “cozy[ing] up to tyrants and dictators.”

“As president, I will never waver in defense of America’s security and ideals,” she declared. “In the enduring struggle between democracy and tyranny, I know where I stand, and I know where the United States belongs.”

She attacked Trump’s character, describing him as “an unserious man” and a fraud who aims “to serve the only client he has ever had — himself.”

And, with an explicitness Biden was never able to summon, she laid out the two parties’ stark differences over abortion, declaring that despite Trump’s efforts to obfuscate his position, “he and his allies would limit access to birth control, ban medication abortion and enact a nationwide abortion ban with or without Congress.”

But while the issues in the race have not changed, identity does matter.

Harris’ sudden ascent to the Democratic ticket has crystallized the contrast over America’s future that would have loomed in the background of a Trump-Biden rematch but which now stands front and center.

The number of foreign-born Americans has soared over the past two generations to levels not seen in more than a century. Immigrants now make up roughly one in eight Americans, and roughly one in four American children has an immigrant parent.

By contrast, immigrants made up fewer than 5% of Americans when Trump was coming of age in the late 1960s and early 1970s.

That sharp increase in the immigrant population has come amid other profound changes in American society, many of which the convention showcased, with a lineup of Black, Latino and LGBTQ+ political figures appearing in prime time. Friends and relatives extolled Harris’ blended household, holding it up as an exemplar of modern families.

All that comes as the GOP, especially Trump’s running mate, Ohio Sen. JD Vance, have declared their support for the family structures and gender roles of the 1950s.

Vance’s positions on women’s roles in society and his jibes at “childless cat ladies” have proven politically toxic. Of the four principals in the presidential race, he has the least favorable public image.

On immigration, by contrast, the public is more closely divided and Democrats face more political peril.

For Republicans, fears about immigration have risen to the top of the political agenda. Nearly 9 in 10 Republicans say the United States should let in fewer immigrants, according to a Gallup poll taken in June. Fewer than 3 in 10 Democrats took that view.

But public concern about immigration goes beyond the GOP’s overwhelmingly white and predominantly rural core. Support for immigrants and immigration has declined notably over the last three years amid deep concern over the border.

Trump and the GOP have vigorously sought to tie Harris to images of border chaos, using it as a part of a broader assault on her as soft on crime and dangerously tolerant of disorder.

“Kamala Harris will deliver crime, chaos, destruction and death,” Trump declared at a campaign event in Michigan on Tuesday in which he called his opponent the “ringleader” of a “Marxist attack on law enforcement.”

In her speech, as in her campaign advertisements, Harris has sought to counter those attacks by stressing her career as a prosecutor.

Her experience in the courtroom, as San Francisco district attorney and as California attorney general have been central to Harris’ political identity, but also a fraught topic in her recent campaigns.

When she launched her bid for the party’s 2020 presidential nomination, that experience played a key role, reflected in her courtroom-inspired slogan, “For the people.”

But as she tried to appeal to the progressive activists who play a major role in Democratic primaries, her law enforcement background turned into a liability, especially after the murder of George Floyd by Minneapolis police in May.

“Kamala is a cop” became a derogatory catchphrase on the Democratic left as she faced criticism over California’s record of imprisoning disproportionate numbers of Black men.

At the outset of this campaign, it was unclear how Harris would present her law enforcement experience. In her initial week as a presidential candidate, she mostly stuck to the part of her resume that is politically safe on the left — talking of her pursuit of white-collar crime and the cases in which she went after fraudsters or held corporations accountable for misconduct.

By Week 2, however, she had pivoted to stress cases in which she prosecuted drug traffickers, rapists and killers.

And she has used that experience as part of her effort to neutralize the border issue.

“After decades in law enforcement, I know the importance of safety and security, especially at our border,” she said Thursday.

She reminded her listeners that earlier this year, Trump killed a bipartisan bill on border security by telling Senate Republicans to vote it down. She pledged that as president, she would bring the bill back to Congress and sign it into law.

That embrace of border enforcement illustrates the tricky task Harris faces over the next two and a half months as she seeks to claim the administration’s popular achievements — reducing the cost of insulin to $35 per month for patients covered by Medicare, for example — while distancing herself from those parts of the Biden record that voters dislike.

Republicans express confidence that by election day, they will succeed in holding her accountable for all of Biden’s failures.

So far, however, voters appear not to blame her for the parts of Biden’s record they object to, several polls have found.

The roughly 10 weeks between now and election day will test whether Harris’ declaration of a “new way forward” will continue to protect her against Republican attacks.

Even as those debates unfold, however, Harris’ identity may be the fulcrum on which the election turns. As large as the policy differences between the two parties are, they may be outweighed by the fundamental clash over whether voters will resist or embrace the changing nature of American society.

What else you should be reading

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The Saturday must read: GOP opposition to COVID vaccines has morphed into a broader vaccine hesitancy.

The L.A. Times special: Biden eked out a win over Trump in Georgia in 2020. Can a surging Harris do the same?

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