Scott Ellsworth’s new book, Midnight on the Potomac, is about the last year of the American civil war and “the crime of the century”: the assassination of Abraham Lincoln by the actor John Wilkes Booth at Ford’s Theatre in Washington on 14 April 1865.

Asked how the book came to follow The Ground Breaking, his acclaimed history of the 1921 Tulsa race massacre, Ellsworth said his thoughts focused on two areas: historical parallels to the modern-day US, and the true crime genre.

“One thing that was driving it was the sense that in the past few years, the nation has never been that divided in my lifetime, and I’m old enough to remember the late 60s and early 70s,” Ellsworth said. “And the only other time we had been so divided was in the 1850s and 1860s, so that was a natural draw right there.

“And I was thinking about, ‘What was the crime of the 19th century in the United States? And it was clearly the murder of Lincoln. And once I dug in and started to turn up some stuff, I realized there was something there.”

A professor in Afro-American and African studies at the University of Michigan, fascinated by the civil war since childhood, Ellsworth knew full well Lincoln is one of the most-written-about figures in history. But Ellsworth is not your average professor. Having been described as “a historian with the soul of a poet”, and having won a PEN/ESPN award for literary sports writing too, he knew he could tell the story his way.

“I’m trying to reach a broad audience,” he said. “I’m trying to reach readers who wouldn’t necessarily, or very rarely, pick up a piece of nonfiction, certainly history. And I was lucky in the sense that I had this surfeit of material that is so great and so dramatic, the question is just how to put it together. Story is very important.

“I’ve got some early responses from folks who’ve read a lot on the subject and said, ‘I never really thought of it in these ways.’ I think I managed to turn up some stuff that most civil war readers aren’t aware of.”

In the popular imagination, Booth has come to be seen as a dysfunctional personality turned lone assassin, the first in a line that includes Lee Harvey Oswald, who killed John F Kennedy in Dallas, Texas, in 1963, and Thomas Michael Crooks, who tried to kill Donald Trump in Butler, Pennsylvania, just a year ago. Ellsworth set out to shatter that idea.

“On the image of Booth, I go into detail about the New York Times, the Chicago Tribune, everybody calling him this genius – people getting turned away by the hundreds from his performances, women trying to storm into his dressing room. The popular conception of who he is [is] just wrong. He’s not that person at all.

“It lives on today. On Broadway right now, there’s the show, Oh Mary! [about Lincoln’s wife] which is very raunchy and very hilarious. But in that, again, Booth is this kind of loser. That’s ingrained in us – that’s who he was, a disturbed loser. He wasn’t. He was a star.

“And so if I can help change your mind and open your eyes to a different version of Booth, then you can start to see him in a different light.”

Booth did not act alone. Confederate conspiracies ranged wide, from planners in Richmond, Virginia, to agents in Canada and in northern states with whom Booth schemed. In November 1864, agents attempted to burn down New York City, an incident Ellsworth recreates vividly. Confederate agents plotted first to kidnap Lincoln, then to kill him.

Last year, as Ellsworth worked, the national spotlight found the Confederate plot, when the leading Trump ally Steve Bannon told a reporter Trump’s frequent use of the word “retribution” on the campaign trail was a nod to codewords used by the plotters.

Events during the plot are familiar too: a near-miss as Lincoln rode from the White House to the Soldiers’ Home in northern DC; Booth’s presence in the crowd for Lincoln’s second inaugural on 4 March 1865, visible in a famous photograph; the actor’s response to remarks Lincoln gave on 11 April, the promise of citizenship for Black men prompting Booth to tell associates: “That is the last speech he will ever make.”

But among aspects Ellsworth holds to new light is a much less-known near-miss, on a frigid night in January 1865 when Lewis Powell, one of Booth’s co-conspirators, hid in the shadows outside the war department, close by the White House, and waited for Lincoln to show.

Ellsworth writes: “Here was his chance. A well-aimed shot, even from behind the bushes, might work. That, or a quick dash for one at close range.

“Only he had not counted on the second man. Probably a bodyguard, and more than likely armed. And then there was the ground itself.

“Could he even run on it at all? What if he fell? Powell hesitated. The two men walked away. The moment was lost.”

Follow Ellsworth to his extensive notes, and they reveal a 1907 memoir by David Homer Bates, one of the first military telegraphists in Lincoln’s war department. That obscure volume and another, on Civil War Weather in Virginia, furnish key details.

Elsewhere on Ellsworth’s wide canvas, a little less obscure but no less fascinating, is Lois Adams, a Michigan newspaper reporter who worked as a government clerk in Washington and sent detailed letters back to her state, which Ellsworth uses to enrich his picture of wartime DC.

“There was this wonderful librarian at Central Michigan University who discovered Adams’s letters and put them together in a book,” Ellsworth said, referring to Evelyn Leasher. “I ran into the book, and the more I read, I just thought of Adams, ‘She’s just dynamite.’ She is a keen observer of lots of things … about Washington during the war. She added such a richness to things, and she saw through things immediately.

“And so I kept inserting her throughout the book, because I think she adds such a fascinating perspective but she sees she’s really undeservedly forgotten. She needs a lot more attention.”

Ellsworth also presents the stories of the former slaves who followed the Union armies to freedom as the war neared its end, and of African American leaders who sought to seize the chance of liberty, the remarkable Henry Highland Garnet prominent among them.

After Lincoln’s killing, Booth escaped into Virginia. After a 12-day chase – the subject of the recent Apple TV miniseries Manhunt – the killer was killed in turn. Lincoln’s body was taken back to Springfield, Illinois, the funeral train retracing his journey to Washington in 1861. Ellsworth concludes his own story at Arlington National Cemetery, across the Potomac from DC, on the grounds of the home of Robert E Lee, the leading Confederate general.

In doing so, Ellsworth asks readers to look beyond the death of Lincoln, to the country he left behind, the “Rebirth of America” of the subtitle to Ellsworth’s book. At the cemetery, in section 27, people once enslaved lie with Black and white soldiers who died for the Union cause. Ellsworth said he set his final scene there in order “to remind Americans of the glories of our past, and of the incredible Americans that have built this country.

“One thing I want people to know is how close we came to losing our country to the Confederacy, of slavery surviving in some form, for a while at least. It’s just by the skin of our teeth that the Union is held together, but it was held together by this remarkable coalition which we’d never really seen before, in the US, of men and women, Black and white, native-born and immigrant people putting aside differences to come together, ultimately, to work for a common goal.

“We need to honor the courage and grit that these loyal citizens showed, to endure those four years of hell. One out of every 50 Americans died during the war. Every family in the north lost somebody, and they were able to hang in there through it all. I want us to recognize that, and to recognize that we have plenty of heroes in our past, and I think it’s helpful to look toward them as some of our institutions are under attack now, and remember that they paid a very high price.

“The runaways, the formerly enslaved, the Union soldiers, they could not have imagined the America that we have today. But we wouldn’t have it, had it not been for them. They helped to build it, and we owe them something.”

• Midnight on the Potomac is out now.