Washington (CNN) -- Editor's Note: This story is from the CNN special "Stories: Reporter" which airs Saturday night at 7:30 pm eastern.
The Wok and Roll is a good place to find sushi in downtown Washington, but a strange place to launch America's most infamous assassination plot.
Yet, in 1865, the building that now houses the eatery, was the boarding house of Mary Surratt. The new Robert Redford directed movie, "The Conspirator," is all about how the Maryland woman allowed John Wilkes Booth to meet with her son and others under her roof to plan the kidnapping of President Lincoln; a scheme that turned to murder.
And in the long ago capital of the Confederacy, Richmond, Virginia, the film has reopened an old debate for historians such as Edward Ayers, president of the University of Richmond.
"If this had happened only a few years later, it would have been a different story," he said roaming across the beautiful campus on warm morning.
"There were a lot of Mary Surratts and a lot of families like the Surratts all across Kentucky, Ohio, Illinois, Indiana; you would see that families were divided on what the right thing was to do."
At the time, four brutal years of civil war had just ended. More than a half million Americans had died. Victorious Northerners were still furious over the dreadful cost of the conflict, mistrustful of Southerners, and when the president was assassinated, they demanded vengeance; if only for their peace of mind.
"There were enemies everywhere," Ayers said, "and there were spies, and there were people whose loyalties simply could not be determined."
Laurie Verge knows the case as well as anyone. She oversees another of Mary Surratt's boarding homes, once a Confederate safe house, now a museum in Maryland, just outside D.C. "It wasn't just Abraham Lincoln that the country was mourning. They were mourning the dead fathers, the dead sons, the amputees and such as that."
Booth stopped at the Maryland Surratt house as he fled, to pick up a rifle hidden inside a wall. You can still see the exact spot where the weapon was concealed.
Another boarder who ran the tavern for Surratt would swear in court, she knew all about it, and was certainly in league with the killer. It didn't matter that he was attacked by the defense as an unreliable alcoholic, the testimony was damning. Surratt was hurt too by her known Confederate leanings, and the fact that she said she did not recognize another conspirator whom she clearly knew. It was all circumstantial, of course, but in the fever following the president's death, enough to have her picked up by investigators.
Verge believes Surratt, who was only in her 40s and already a widow, had seen enough of life and war to not be surprised.
"I think she expected to be arrested. This lady is cool as a cucumber. She is not the least bit frazzled, the way she is talking to them. She is sort of haughty, and it was like, she knew this was coming. She was prepared for this," Verge said.
But does that mean she was guilty of the assassination?
Ayers has his doubts. "You know, you look at it, and I think the evidence is inconclusive."
The movie underscores Surratt's illness during the trial, the brutal conditions in which she was held, the frustration for federal authorities over Booth being killed during the hunt, and the fact that Surratt's son, John, was the only suspect they could not find. It suggests if she had revealed her son's whereabouts, she might well have been shown leniency.
Still, her lawyer was not the reluctant amateur depicted in the film, but a strong supporter of the Confederacy, and she had a much more robust defense than the movie implies, according to Verge.
"There were lots of defense witnesses brought in to testify to Mary Surratt's loyalty to the Union," Verge said. "They brought in priests who testified that she was a good, Christian, loyal woman, and therefore she could not be a part of murder and things of that nature."
Ayers, however, believes Surratt was an easy target: a proud Southerner, when that alone was widely seen as treasonous and a woman at a time when women were held particularly accountable for the success or failure of their households.
"One of the lines that they used at the time," he said, "was that she kept the nest that bred the vipers. So she, in many ways, is the projection of what a mother gone wrong looks like."
The military tribunal certainly seemed to think so. They sent her and three other conspirators to the gallows. Many people were squeamish over the idea of such a sentence for a female, and certain she would get a last minute commutation to life in prison. But less than 90 days after President Lincoln's assassination, she became the first woman ever executed by the U.S. government.
In the movie she walks bravely to her death, but Verge has studied the record enough to know Surratt was not so stoic climbing the steps to the noose.
"She was being supported on both sides by gentlemen trying to get her up there, and her last words that we know of were 'Don't let me fall, don't let me fall.' "
Surratt's son was eventually located and tried two years later in a civilian court. He was not convicted; adding to the argument that has raged ever since: Would she be convicted today?
Verge said Surratt was certainly aware of the plot, so "if she were to be tried on the grounds of conspiracy, yes, I believe she would be."
But executed?
Ayers too says it appears that she committed treason, "but not treason worthy of death, it would seem to me."
Mary Surratt's remains were released to her family four years after her death and lie in Washington's Mount Olivet Cemetery.
Her grave is only a few miles from the place where the president was killed and still surrounded by as much controversy as the day she died.