Imagine waking up on 4 November 2020 to discover America has elected a man whose knowledge ranges from the Puritan origins of the phrase “city on the hill” to the details of how to modernize sewers with wifi connected sensors.

Imagine that this man is also an Afghanistan veteran who understands that “truly grasping and defeating the logic of suicide terrorism” was beyond the capacity of Congress or the Bush administration after 9/11; a student who connected the dots in high school between the values of his theology class and those of Amnesty International; a graduate of Harvard and a Rhodes scholar who got a first at Oxford; the mayor of a small midwestern city who managed to revitalize it in less than eight years; someone who has never slept with a porn star, and who married the very first person he fell in love with.

And imagine this is someone whose spouse just happens to be a man – which, as Stephen Colbert pointed out on The Late Show, is “only the third thing” you learn about this presidential candidate.

This is part of the life story Peter Buttigieg tells in his beautiful new book, Shortest Way Home, the best American political autobiography since Barack Obama’s Dreams from My Father.

Buttigieg is the 37-year-old mayor of South Bend, Indiana. Brimming with midwestern authenticity, he captured a large portion of CNN’s audience earlier this month in his first nationally televised town hall. That put him comfortably over the Democratic National Committee’s threshold of 65,000 individual donors which governs qualification for the forthcoming debates.

The son of a Notre Dame professor whose family hails from Malta, Buttigieg’s is a classic American success story. It begins with acceptance at Harvard, followed by his winning the John F Kennedy Presidential Library’s annual Profile In Courage Award for a high-school essay.

At the ceremony, Buttigieg met Senator Teddy Kennedy, who offered him an internship. “It felt like I had been handed a ticket to the major leagues,” he writes. He had been. His freshman room at Harvard had a plaque listing former residents including Cornel West and Horatio Alger.

Buttigieg writes unusually well for a politician, although his unfortunately frequent use of “impact” as a verb lends credence to his publicist’s insistence that the candidate wrote every word himself – unlike JFK, who found the best talent money could buy to help him write a Pulitzer winner.

Buttigieg sees 9/11 as the turning point for his generation, when it became clear “irony and apathy wouldn’t dominate our years after all”. Imagine, then, a president who can write a paragraph like this:

We see how often war and terrorism are driven by the dynamics of globalization, the distribution of wealth and the consequences of technology. Like laws of physics, these forces were animating our affairs all along – which should have been no surprise to people from a place like South Bend, a city wrestling such forces long before newspapers gave us terms like ‘globalization’ and ‘rust belt’.

His service as mayor of South Bend was interrupted when he was called up as a naval reservist to go to Afghanistan as an intelligence analyst. His service also overlapped with Mike Pence’s time as Indiana’s governor. Despite Pence’s virulent homophobia, Buttigieg managed to work with him.

It was, he writes, “… a demanding exercise in compartmentalization. I knew that he held the keys to economic policies that would advance our city’s interests … But he also revealed himself to be gripped by hard-right social ideology … It was part of my job to work well with anyone who could help the city.”

Like the Best Little Boy in the World celebrated in Andrew Tobias’ landmark gay novel in 1973, Buttigieg was so busy doing everything a little better than everyone else he did not get around to coming out until his 33rd birthday. He took that risk in the middle of his re-election campaign, with an op-ed in the South Bend Tribune.

He did it because he realized it was the only way he could have “a meaningful personal life”. This was something no American politician thought was possible 40 years ago, which is why Ed Koch, the three-term mayor of New York, never said he was gay in public – and, as a result, never had a meaningful personal life.

Buttigieg signed his city’s ordinance forbidding discrimination on grounds of sexual orientation in 2012, but he writes that “it was not exactly applicable in my case”. Most reaction was either “supportive or didn’t care”, except for the man who stopped delivering his newspaper for a few days because he didn’t want to give it to “one of them”.

When Buttigieg’s elderly neighbor Kathy noticed, he writes, she asked: “Has he done anything to you?” The man never missed a delivery again.

Buttigieg met his husband online, and their first date included a visit to the South Bend Cubs. They made it to the sixth inning before they ditched the game for a walk by the river.

“I felt the slight brushing of his hand coming closer to mine,” he writes, “and I took hold of it. Nothing in my life, from shaking hands with a president to experiencing my first rocket attack, matched the thrill of holding Chasten’s hand for the first time. I was electrified. We got back to the car just as the post-game fireworks began, and as the explosions and lit colors unfolded over us, he went in for a kiss … It only took a few weeks for me to acknowledge the obvious: I was in love.”

Is it too much to imagine that America could elect a gay president? I don’t think so. If the disaster of George Bush’s administration was sufficient to elect the first black president, I believe the catastrophe of Donald Trump could be just enough to put the first openly gay man in the White House. Especially a man like this.

• This article was amended on 18 March 2019 to correct a misspelling of the first name of Cornel West as Cornell.