It’s thought that Biden is of an age to prevent him running for a second term and that history would beckon once more for Harris.
At moments like these America typically goes large. The pandemic has changed all that.
Coronavirus precautions reduced a most significant moment in the United States’ political and cultural history to a high school stage.
The gym hall of Alexis DuPont High School in Wilmington, Delaware, provided the sanitised setting for the introduction of America’s first black woman to run for the White House in a major party.
The announcement was sparsely attended by a restricted media recording every word and its echo in a venue too big for this crowdless event. But in a place of learning, it was a lesson in history as it happened.
“Very emotional, it brings me tears of joy. It is history, like never before,” said Pat Rigby, as she sat on the kerb of the school car park reading newspaper coverage of the Kamala Harris appointment.
An African-American woman, she was the first, by hours, of a small, curious crowd to gather in the school grounds for an exterior view of the spectacle.
Pat, 62, had travelled 60 miles from Maryland, Virginia. Hers a voice from the black community. “I know where black folks have been, what they’ve been through and this is huge because we’ve waited so long to be seen and heard.
“Our skills, our abilities, our knowledge had been overlooked so many times. Now, with Kamala in there, people will start to pay attention a little bit more.”
The sentiments on the street matter to Harris, Biden and the Democrat project, particularly where African-American voters are concerned.
A percentage drop in the party’s black vote was damaging in key swing states in 2016. Reversing a post-Obama sense of disenfranchisement would provide necessary traction in 2020.
To a black constituency that recognises what it can do for Kamala Harris, she acknowledged the need for her party to reciprocate when she spoke in the school hall.
She used this campaign event to reinforce racial justice as her signature issue, repeating a pledge to root out systemic racism, invoking the civil rights movement she said had brought her immigrant parents together and her own, small part as a child – “I was there, strapped into my stroller.”
The California senator said America now faced a “moral reckoning” with racism and systemic injustice, that this moment was one of “real consequence for Americans” and that “everything we care about is on the line”.
In creating a narrative for the campaign ahead, the ability of Kamala Harris to carry a multi-racial coalition behind the Democratic ticket will have been clear to Joe Biden.
Her campaigning value has been elevated by the timing and circumstances in a country facing a reckoning on racial injustice. She herself says her personal and professional background makes her well-placed to implement criminal justice reform.
The Biden-Harris ticket is anchored in the centre-left of the Democratic party. They are political soulmates engaging in a campaign that Joe Biden once again styled as a fight for what he called the “soul of the nation”.
Joe Biden had previously said he wants an administration that “looks like America” and, in choosing his running mate, he faced pressure to follow through on the pledge.
African-American women vote in higher numbers for the Democratic party than any other demographic group and party activists had made it known they expected due recognition and reward.
The choice of Kamala Harris is founded on both political advantage and personal friendship. Inside Alexis DuPont High, he called her an “honorary Biden” and both spoke emotionally of their connections to Beau Biden, Joe’s son, who died of cancer in 2015.
There was talk, too, of another mutual and significant influence. Much has been made of Joe Biden’s wish for a running mate with whom he can do business and he indicated that he calibrated his choice according to the relationship he had as vice-president to Barack Obama.
He was told as vice-president, he said, to always tell the truth, ask the tough questions and to challenge the president’s assumptions.
Kamala Harris has demonstrated through a career of ground-breaking achievement that she can fulfil the brief and, perhaps, go beyond. Indeed, coverage of her selection here in the United States consistently frames it as part of a future plan to position her as America’s first black president.
The thinking goes that Joe Biden, at 77 years-old, is of an age and frailty to prevent him running for a second term and that history would beckon once more for Kamala Harris.
Of course, they first need to win the White House on 3 November and there’s still more than two months of hard campaigning between now and then.
Much will depend on how they perform far from home ground in Wilmington, Delaware amongst swing voters in swing states.
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In energising their voter base with the announcement of their vice-presidential nominee, the Democrats have stirred opponents too.
Within seconds of the selection, Team Trump rolled out a political ad branding her “phoney” and Donald Trump dismissed her as “nasty”.
What matters most on any party ticket is the person running for the top job but opinion polls indicate President Trump hasn’t felt the benefit of negative campaigning against Joe Biden.
Kamala Harris presents a new target. Joe Biden introduced his running mate as a tough, experienced fighter who never backed down from a challenge.
The career prosecutor will need all those qualities as she prosecutes the case for change.