As social media birth announcements go, Jacinda Ardern’s handheld Facebook Live of herself and her newborn Neve Te Aroha Ardern Gayford is charming.

New Zealand’s prime minister introduces her new baby with radiant sincerity. She thanks her midwife and the hospital staff for their generous professionalism, and New Zealanders for their kindness and gifts. With a quick cutaway, she even jokes with the baby’s father about his “dad jumper”.

But as a political communication, the video is matchless. In an epoch overcast by growing shadows of reenergised rightwing authoritarianism, Ardern’s public hospital nativity offers a luminous symbolic affirmation of her leadership not just of New Zealand, but of the western electoral left.

Play Video 1:45 Jacinda Ardern reveals name of baby daughter Neve Te Aroha – video

The leader of the first Labour government in New Zealand for a decade shares the explicit left agenda for investment in health, education, climate action, public housing and social justice. Ardern’s pledge to build “a kind and equitable nation where children thrive, and success is measured not only by the nation’s GDP but by better lives lived by its people” is the ancient standard of our side.

Yet while recent celebrity left leaders have failed to win elections, or even nominations, Ardern gained the leadership of her party seven weeks out from an election, and she won.

She nearly doubled the Labour vote, wrangled herself into office with a complex multiparty coalition, and just passed a social democratic budget. Polls have held. The most recent gives her party and one coalition partner, the Greens, enough votes to govern between them. Her personal approval rating is a thumping 76%.

To understand why is to look beyond policy and into her representation of it. What distinguishes Ardern is her active embrace of what Walter Benjamin referred to as “the time of the now” and the diverse and complex identities of a community that no longer sees itself as by, for and of propertied, straight white men. Doing so shatters a traditionalism that imprisons the left even as much as it inspires today’s right.

Ardern is the first elected world leader to ever go on maternity leave. Of this, former NZ Labour prime minister Helen Clark noted: “These are the kinds of practical arrangements working women make the world over – the novelty here is that it is a prime minister who is making them. The signal this sends, however, is that this is life in the 21st century.”

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But the insight is enhanced by considering theorist Stuart Hall’s old observation that “Politics does not reflect majorities, it constructs them.” Local NZ commentator, Michelle Duff, lauded the events of Ardern’s maternity as a national achievement, writing, “Let’s just take a moment to appreciate that we, as a nation, have pushed the boundaries and created an environment where this can happen.” Clark said for New Zealand, this was merely “evolution”.

Observe, also Ardern – who is Pakeha, not Māori – meeting the British queen wearing a Kahu huruhuru: a Māori feathered cloak “bestowed on chiefs and dignitaries to convey prestige, respect and power”. It was a demonstration of a status conferred, and not stolen, and a representation of a New Zealand unafraid to show pride in its indigenous past even as it engaged in diplomatic pleasantry with its colonial one.

Little wonder that “the prime minister’s empathy with and interest in the indigenous people of New Zealand [is] improving relations between Pakeha [European] and Māori faster than at any other point in history,” a spokeswoman for Ngati-Haua, of the Tainui federation of tribes, has said.

In this case, the spokeswoman was responding to Ardern’s choice of “Te Aroha” as her newborn’s middle name, which refers both to a mountain where Ardern grew up an a Māori language word for love. “Everybody knows what aroha means,” says Ardern in her baby video. Even though“everybody” doesn’t, every New Zealander certainly does. Ardern’s grasp of the local – from giving birth in a public hospital, to announcing her pregnancy on Instagram – is exemplary. The town of Te Aroha is planning a celebration of their namesake baby’s birth; plans are to paint its buildings pink.

The achievement here is Ardern’s marriage of the old left economic program with the new explicitness of identity politics – and it resonates because it’s sincere. Failure to bridge these positions will doom all of us.

Theorist Wendy Brown explained this in her 1999 essay of prophetic relevance to today’s particular political moment. Brown writes of a “left melancholy” as a state of wilful, purist political nostalgia, in which the left “has become more attached to its impossibility than to its potential fruitfulness, a left that is most at home dwelling not in hopefulness but in its own marginality and failure, a left that is thus caught in a structure of melancholic attachment to a certain strain of its own dead past”.

It’s hard not to see this melancholy in the celebration of electoral defeats as somehow moral victories, when across the world the present, visible reality for women, indigenous people, the LGBTQIA+ community, refugees and so many others is that electoral outcomes represent life and death stakes.

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The alternative proposition is to remember “that the people closest to the pain should be closest to the power” – and they should pursue power, without shame. This statement was quoted by the victorious Alexandria Ocasio-Cortes, who delivered a shock upset to the established order when she won a Democratic primary in New York this week.

In a party where the top three positions are held by septuagenarians, commentator Dana Milbank saw Ocasio-Cortes’s election not as a disruption to the Democratic trajectory but an event of happy augury. “The emerging electoral majority that already dominates the party and will soon dominate the country, [is] progressive, young, female and nonwhite. It is no accident that Ocasio-Cortez, a 28-year-old Latina, is all four,” he observed.

If today’s left is going to stand a chance against an ascendant, muscular right, my hope is that she and other avowed socialists emerging within her electoral generation eschew the stale temptations of left melancholy for energising examples of a visionary left that looks as different to its past as a pregnant woman in a feathered cloak does to a room of suited men.

“Strong men” of the right are now lining up governments from Italy to Turkey to the United States. The times of the now are ones in which we can construct majorities of a diversity they cannot – and do not wish to – represent. We can hope the influence of Jacinda Ardern and Alexandria Ocasio-Cortes spread, or we can ensure that it does. The stakes for the marginalised remain life and death.