Robert Redford's The Conspirator might be about the military trial of a woman convicted in 1865 of conspiring to murder President Abraham Lincoln, but it has obvious relevance to today's debates about the use of military vs. civilian courts to try those accused of terrorist or military actions against the United States and the right of even the most notorious defendant to have a fair trial.

That's why more viewers than just Civil War buffs will be interested in The Conspirator," recently out on DVD (Lionsgate, $29.95/$39.99 Blu-ray, rated PG-13). It's the story of Mary Surratt, the owner of a boarding house in Washington, where John Wilkes Booth, her son John Surratt (a Confederate spy and courier), and other conspirators planned the murders of President Lincoln, Vice President Andrew Johnson and Secretary of State William Seward. (While Booth succeeded in killing Lincoln, the attack on Johnson was aborted and Seward survived his knife wounds.) Mary Surratt also was accused of more directly aiding the conspirators by allegedly providing a spy glass and weapons to Booth as he tried to escape the authorities after the assassination.

The murder of President Lincoln took place less than a week after General Robert E. Lee, commander of the Confederate Army of Northern Virginia, surrendered. But the war was not yet over. Confederate President Jefferson Davis was still at large. Rebel armies persisted in North Carolina (75,000 strong) and Texas. Booth and his fellow conspirators hoped their action would "decapitate" the North's leadership, in the words of historians interviewed in the DVD documentaries The Conspirator: Mary Surratt and the Plot to Kill Lincoln and Witness to History, and win for the Confederacy a political victory it could not win on the battlefield.

Although Surratt, played by a deglamorized, dark-haired Robin Wright, is the title character in The Conspirator, the movie revolves around her young defense attorney, Frederick Aikens (James McAvoy), a former U.S. (Union) Army Captain who had been wounded in battle. Redford's film highlights Aikens' initial reluctance to defend Surratt, his growing belief that she was receiving an unfair trial before the military tribunal and the bond that developed between attorney and client.

Among the villains in the film are not only Booth and the other conspirators -- though not Mary Surratt, who is portrayed more ambiguously -- but Secretary of War Edwin Stanton (Kevin Kline) and U.S. Army Judge Advocate General and chief prosecutor Joseph Holt (Danny Huston). According to the film, it is these two men who first insisted on quick military trials for the arrested conspirators and then "fixed" the trial and sentencing to ensure that the key defendants would be convicted and executed.

In his DVD audio commentary, Redford says that while his movie's main story was the changing relationship between Mary Surratt and Aikens, he also wanted to tell a story "that nobody knows about [the conspiracy] that's connected to a story that everybody knows about" (Booth's assassination of Lincoln). Redford maintains that he didn't want to focus on the historical "parallels" between the Surratt case and present-day issues. This comes across as somewhat disingenuous, as such parallels will be obvious to most thoughtful viewers.

The Conspirator was made under the auspices of, and financed by, the American Film Company, as the first in a series of movie projects about true stories from America's past. (Films about Paul Revere and John Brown are currently in development.)

Sometimes these historians disagree with Redford and the interpretations he and screenwriter James Solomon put forward in The Conspirator. Redford maintains that the key questions of how much did Mary Surratt know and how much was she involved in the conspiracy remain unanswered "because she was put to death in a trial that was so unjust." Yet Col. Fred L. Borch, retired U.S. Army historian and lawyer, probably represents the consensus view of Civil War historians when he states that "the evidence is sufficient to find her guilty."

Other historians not included in the DVD or American Film Company discussions have raised additional problems with The Conspirator. Writing on the University of North Carolina Press' Web site commemorating the 150th anniversary of the Civil War (bit.ly/mYButT), Elizabeth D. Leonard of Maine's Colby College disagrees with the film's portrayal of Mary Surratt as "a noble woman driven only by her maternal instincts to try and save her son," who had disappeared. Furthermore, Leonard objects to Redford's unfair portrayal of "the federal government -- particularly through the characters of Edwin Stanton and Joseph Holt -- as the purely vengeful, bullying victor, determined, for whatever reason, to continue punishing its now helpless and compliant former enemy."

It should also be noted that while Redford in his commentary and the historians who appear in the DVD documentaries discuss the crucial issue of slavery and its abolition and the impact of that on Mary Surratt and the other conspirators, at no time does The Conspirator even mention what the conflict was all about. All viewers learn about Surratt's viewpoint is that she supported the South in the war. Nor does Redford's film reveal the important fact that Mary Surratt had owned slaves in Maryland, but was forced to sell them to pay debts and because Maryland formally abolished slavery in 1864.

As a movie The Conspirator is well made and well acted, with exquisite attention to period detail. While one might appreciate Redford's craft and the excellent performances he elicited from his cast, I found it difficult to develop any sympathy for the cause of Mary Surratt. Regardless of the depth of her involvement in the conspiracy to murder the president, had she spoken up about what was being planned in her boarding house she could have prevented the murder of Abraham Lincoln -- and the dire consequences this act had on the future of America in the age of Reconstruction.

But that might be Redford's ultimate point -- that even a person accused of conspiring to commit one of the most heinous crimes in our country's history deserved a fair trial. His film certainly provokes a useful discussion of that and related matters.

First Published August 25, 2011, 4:00 a.m.