I’ll fight to the grave on this: Joe Biden was one of the most effective vice presidents in the history of the United States.

It’s hard to recall now, but in 2008 Biden’s experience and genial demeanor afforded a small but important subset of white American voters with the confidence to vote for the first black president. Once in office, though, Biden transformed into a very different figure than Token White Grandpa: he became the Crazy Uncle of the White House, the figure who’s prone to blurting out what everyone else was thinking.

In politics, Biden’s variety of straight shooting can often be a liability. But from the moment when he accidentally told President Obama on a live mic that passing the Affordable Care Act was “a big fuckin’ deal,” Biden became lovable. He grew into a persona that he’d cultivated his whole life. (One of the major scandals of the 2008 Democratic primary arrived when Biden called Obama “articulate and bright and clean,” playing the clueless old white dude to the hip young Senator from Illinois— a move which allowed Obama to graciously forgive Biden, and, by proxy, those thousands of other white people who have accidentally said something offensive in the presence of a person of color.)

The Onion’s brilliant trashy Joe Biden character sealed the deal, but the truth is that Biden always loved to promote the image of himself as a hair-trigger soothsayer. He famously came out in support of gay marriage before Obama did, causing no small amount of consternation in the West Wing. And the media loved to fixate on Biden’s gaffes, but what most reporters missed at the time was that Biden was performing a function not unlike Luther, Obama’s Anger Translator in those old Key & Peele sketches:

Biden represented Obama’s untapped id — he voiced the president’s rage, his joy, his sadness, his disgust at the worst ideas the Tea Party had to offer. And he served as America’s id, too; in 2012, I wrote about Biden’s amazing kamikaze attack on then-VP candidate Paul Ryan in the first and only vice presidential debate of that cycle. In the aftermath of Obama’s horrendous first debate performance, Biden openly laughed at Ryan’s Ayn Rand-inspired ideas, thereby giving liberals permission to do the same.

So imagine my surprise when the first chapter of Biden’s memoir, Promise Me, Dad: A Year of Hope, Hardship, and Purpose, inspired not laughter or catharsis but rather tears. That first chapter, “Biden Family Thanksgiving,” is the best of Promise. Detailing Biden’s family ritual of heading to Nantucket for the holidays, “Thanksgiving” is a tender and teary-eyed reminiscence of the tradition, tracking the growth of Biden’s family from a small nuclear unit to a large extended clan of adult children and vivacious young grandchildren.

The audio version of Promise is read by Biden himself, and you can feel the warmth and the love in his voice as he narrates the passage of the years and the happy expansions of the Biden family. And his voice turns, too, when the family traditions go sour. First, a beloved part of the Thanksgiving rituals is swept from the planet. And then Biden’s son Beau is diagnosed with brain cancer. And after that, Joe Biden’s life quickly starts to fall apart.

Anyone who ever heard Biden talk about his son Beau — a soldier, an Attorney General of Deleware, a gubernatorial candidate, a presidential hopeful — knows that Biden worshipped his boy. Biden placed in Beau more than just a father’s pride; he expected Beau to go further than he did, to finish the work that he started. That’s a high expectation for any child to live up to, but when your father is one of the best-known senators in modern times as well as a popular vice president, that legacy likely seemed insurmountable.

Biden’s loving portrait of Beau demonstrates that his son need never have worried about disappointing his dad. (The son was “even more popular than his father,” Biden chuckles warmly on the audiobook.) Even now, Biden is in awe of Beau — his service, his quiet dignity, his capacity for strength — and Promise is a tremendous testament to that bottomless well of love.

In Promise, Biden recounts what it was like to serve as the vice president for Obama in his second and final term, even as he had to hold his family together during the last few months of Beau’s life. As an emotionally compelling political memoir, Promise has very little competition. The portions dealing with Biden’s feelings of helplessness and his grief and his sorrow are tremendously affecting. Several of the passages read by Biden brought me to tears.

But there’s a shadow across this book, and it’s impossible to ignore.

Is Joe Biden going to run for president in 2020? It seems improbable, given that he’ll be 77 years old. But having read Promise, I have to say that it sure seems like he’s considering it. The political chapters of Promise read like the modern variety of political memoirs, which is to say that they’re safe and inoffensive and shamelessly self-laudatory.

Not every politician who writes one of these memoirs actually runs for the presidency—Elizabeth Warren published a memoir, A Fighting Chance, in 2014 that felt as nakedly ambitious as any pre-presidential memoir I’ve ever read — but these memoirs are always at least a sign that the politician is considering a run. With the bland incantations of policy and the staid laundry lists of accomplishments, they usually can be said to serve no other purpose than as a trial balloon for presidential aspirations.

In fact, a good share of Promise is taken up with Biden’s deliberations of whether or not he should run for president in 2016. He writes about an informational visit from Hillary Clinton before she announced her candidacy, in which both would-be presidents feel each other out as potential rivals. (Clinton “didn’t quite believe that I was entirely sincere” in his uncertainty on a 2016 presidential run, Biden writes. “But I was.”)

He writes candidly about his 2016 assessments later on in the book, weighing his belief that he’s genuinely the best-positioned candidate to assuage the fears of economically anxious Americans against the crippling grief that Beau’s death visits upon him. These deliberations are fascinating, and they feel genuine, a significant part of Biden’s journey through heartbreak.

Don’t get me wrong; I ‘m not arguing that Promise should be apolitical. In fact, the chapters where Biden whipsaws back and forth between his dying son’s hospital bed to a conference on the future of the Ukraine perfectly capture the immense pressure Biden was functioning under. And the passage where Biden meets Vladimir Putin is jaw-dropping. First Biden recalls George W. Bush’s fatuous statement that he looked into Putin’s eyes and got a measure of soul, and then Biden says to Putin:

‘Mister Prime Minister, I’m looking into your eyes,’ I told him, smiling. ‘I don’t think you have a soul.’ He looked at me for a second and smiled back.

‘Then we understand each other,’ he said. And we did.

That’s powerful stuff: intense, plain-spoken, and more than a little braggadocious. That the faceoff with Putin falls in between scenes of Biden agonizing over the loss of his son only makes the whole thing feel more real somehow. It’s easy to forget that these larger-than-life personalities — caricatures, really — we imagine at the heads of state are human, with human fears and failings. The vulnerability that Biden displays is more than refreshing — it’s courageous.

But we keep coming back to the unspoken questions of Promise.

Should Biden have run for president in 2016? Who knows? It’s true that he perfectly blended the establishment chops of a Hillary Clinton and the working-American empathy of a Bernie Sanders. It’s possible that Biden could’ve ridden up the middle between the two candidates to victory. And it’s also possible that Biden — with a young, dynamic vice president at his side — might have been better equipped to appeal to the working class and shake off Donald Trump’s weird magnetism.

But that’s a hypothetical. The real question that Promises silently asks: Should Joe Biden run for president in 2020? I don’t think so. While he’s one of the most gifted blue-collar politicians in the business today, Biden’s close ties to Obama would likely make the presidential campaign a relitigation of old battles, when instead the Democratic Party must be relentless in its quest to present a bold new future for the nation. Combine that with Biden’s age and his infamous handsiness in a post-Weinstein age and you’ve got a calamity in the making.

The thing is, running for president has nothing to do with destiny. It’s all about timing. If you don’t seize your moment exactly when it arrives, you might never be president. A two-term Senator Obama running for president after President Hillary Clinton’s two terms in office would likely not inspire the same fervor in the American psyche that the upstart young Obama did.

It seems likely now that Biden’s moment has passed, that the last clear shot he had at the presidency was lost to an unthinkable personal tragedy. But there are many worse things in the world than not being president. Biden’s persona has developed a remarkable complexity through his decades of public service, and the American public has demonstrated a deep and abiding love for him. I have no doubt that he will continue to shape the American story for as long as he’s willing, and Promises marks a bold new step in his ongoing story of evolution.