THE story goes that President Abraham Lincoln walked out of the White House in the middle of the night on February 20, 1862. He crossed Washington DC to Oak Hill cemetery, went into the crypt of his late son Willie, and sat there alone at his coffin.

Willie had died of typhoid fever earlier that day, at the age of 11. His father, somewhat preoccupied through the boy’s short illness by the escalating civil war, was now so possessed by grief and guilt that he may even have cradled the corpse. This anecdote is verifiable in some particulars, and probably apocryphal in others.

But it has haunted George Saunders since he first heard it from a friend while passing by that graveyard decades ago. He envisioned a tableau of sorrow – the president amid the moonlit tombstones – that eventually came to form the abiding image of his new book, Lincoln In the Bardo. The “bardo” is a term from Tibetan Buddhism, referring to the transition state that comes after death and before rebirth, and Saunders himself is a practising Nyingma Buddhist.

“Though still very much an amateur”, he says, speaking from his snowbound home in upstate New York. Born in Texas, raised in Chicago, and educated as an engineer – he used to work in the oil fields of Sumatra – he now teaches English at Syracuse University, and describes himself as “an old hippy”.

Professor Saunders also worries that he often sounds “a bit new agey” in conversation. In fiction, he takes pains to avoid the “excruciating earnestness” that his generous sense of empathy may tend to bring out. Thus far, he has spent his career as an author writing short stories set in bizarre historical theme parks, futuristic drug-test labs or quasi-dystopian suburbs; all populated by unhappy Americans whose speech patterns and thought processes are heavily mediated by corporate philosophy and ad-speak.

His collections, from Civilwarland In Bad Decline to Tenth Of December, have been so highly acclaimed as to make sycophants of book critics, and expand a cultish readership into an international fanbase. In 2013 Saunders made the Time Magazine list of the world’s 100 most influential people. Today, publishing his first novel at the age of 58, he finds himself talking about Abraham Lincoln in the chaotic early days of the Trump administration. His timing might be auspicious, or simply unfortunate.

“I’ve tried to stay quiet about what’s happening right now, or at least to resist punditry,” says Saunders. “There’s a Buddhist thing where you take the blame on yourself. So, any pain or consternation I’m feeling comes first from my own misunderstanding, right? Like a lot of liberals, I thought I knew what my country was, and my country said, ‘hey dummy, you don’t’. And you might talk about opening yourself up to the world, but this is what it actually feels like. It’s not always pleasant. Sometimes it really sucks.”

The current president is now making even the worst of his predecessors look a little better. George W Bush seems almost scholarly by contrast. Richard Nixon’s feverish deceits appear comparatively benign and statesmanlike. But Abraham Lincoln, who was surely the best of them, is cast into brighter relief: a Republican saint, an American Jesus.

“A Christ figure, yeah,” says Saunders. “It’s so tempting to present him that way. I mean, nobody knows Lincoln, but everyone projects onto him. People always talk about his kindness, and what I think they mean is he saw suffering and actually felt it. We have this image of a melancholy guy who took it all on himself, but who knows, really?”

Could the critical difference between the 16th president and the 45th be that the latter has never suffered, and appears to have no feeling for the suffering of others? “I think he probably has suffered in his own way. He seems … broken on some level.” As regards the former, Saunders has minimised his presence in this book.

“For the purposes of fiction, I’m not asking ‘who is Lincoln?’. I’m just guessing at who he might have been on this particular night, and trying not to f*** it up when he comes in the frame. My aesthetic principle was, this is not a biography. The less you say about him, the less you have to lie.” Indeed, the end result doesn’t read much like a novel either.

Saunders has instead composed a transcript of overlapping testimonies. In places, he has used direct quotes from primary sources and real American historians. But most of the voices belong to a chorus of befuddled, disembodied spirits, observing the president’s sad vigil from the weird limbo that surrounds their own burial plots.

“Ugh, ghosts,” he says, recalling his initial reluctance to use the residents of Oak Hill cemetery as narrators and witnesses. “But I needed them, because there was nobody else around, and I didn’t want Lincoln just sitting there, soliloquising.” Perhaps it’s a mark of a trained engineer that Saunders sees fiction as “the accumulation of micro-decisions, which to me are the fundamental units of art.”

“My process is quite non-conceptual. Working on a chunk of prose, you’re just trying to make it acceptable to yourself. And if your talent is constricted like mine, you have to spotlight the things you can do, and divert from what you can’t. Almost like a magician I guess.” In this case, his formal approach comes from his lack of confidence, or interest, in rendering the past through detailed descriptions of clothing, furnishings, contextual accoutrements. “Amen to that,” he says. “ When I think about describing 19th-century rooms, or producing a realist historical novel, I just cringe and I don’t want to do it. ”

The ghosts themselves are animated by whatever joy and sadness gives them a lingering attachment to this world, making them unable to truly pass on, and unwilling to admit their condition. Hans Vollman, for example, is buck-naked and tumescent in his spectral state, having died just before consummating his marriage. His friend Roger Bevins III committed suicide over unrequited love for another man. Bereft of life’s sensual pleasures, he is now given to wistfully listing them: “Grass, sun, beer, bread, quilts, cream …”

In this respect he often sounds like Walt Whitman, and whispers of other bygone American authors can also be heard beneath the chatter of the book. “Whitman’s in there for sure,” says Saunders. “Hawthorne, Melville, Faulkner. Like a lot of romantic writer types I have a visceral love for country. Not in the flag-waving sense, it’s more to do with the thousand little vistas that appear in your mind when you think of the great poets of your nation.”

The voices that comprise the novel are generally contrary too. Whether speaking from the afterlife or first-hand contemporary accounts, they cannot agree on the size and shape of the moon that night, or the colour of Lincoln’s eyes, or whether he was sobbing. “My friend remembers incorrectly,” says Vollman of Bevins, and vice versa. Their dialogue resembles a Twitter feed, pinging between perspectives. Saunders hit on this format in an early draft, inspired by the layout and conflict-potential of instant messaging.

“I liked how it looked on the page, that eruptive quality. But a Twitter feed is really just a kind of technologised instinct, with people talking past each other on the basis of their own intense projections. I think cavemen were probably doing the same.”

Which is to say, he wasn’t trying to be timely. Even in his more science-fictional short stories, Saunders is only concerned with the technical or satirical aspects of his imaginary futures insofar as they stress-test the human condition. He is something of an essentialist.

“I think we’re a bit like those wind-up toy robots. If you put it down on a table, or on grass, or in water, it exhibits a different range of movement. Our humanness is always there, and doesn’t really change. But put us in 17th century France or 25th century America, and we might move differently. In my writing, I try to put the robot on tables so strange that it’s essential workings are revealed more quickly and clearly.”

Readers may feel equally exposed by their reactions. At this point, Saunders has achieved a mastery of effect that makes Lincoln In The Bardo so funny and sad as to wring both kinds of tears from your eyes. But if he ever attained what the Buddhists call enlightenment, might he not move beyond all this, and have no further need for literature?

“Somebody once told me, ‘worry about that when you get there’. I can only speculate here, but my feeling is that there’s no contradiction, that being more aware, more nakedly in touch with your own fluctuations, can only be good for a writer.”

Between meditation sessions, he is no less anxious than anyone else about the state of the material world. Through his long years of working on this new book, he was not to know how it would resonate on publication. That said, he teaches Tolstoy and Isaac Babel to his students, and shares their frequent astonishment at “the deeper currents of fiction, the way they flow into the present moment”.

Lincoln In The Bardo, set so far in the past, carries some of the same spooky energy, as the title character turns from his private grief to his public responsibilities. The ghost of a dead slave named Thomas Havens looks into the mind of the president, and sees as much doubt as resolve. “There was so much to do, and he was not doing it well, and if done poorly, all would go to ruin … ”

How pleasant, and how painful, to think that all might yet be saved if the serving American president would only read this, and weep.

Lincoln In The Bardo is published by Bloomsbury, £18.99