Robert Redford’s new period piece The Conspirator is a welcome gift for history buffs everywhere. The film sheds some much-needed light on one of the greatest injustices ever perpetrated by the United States government on one of its own citizens. The heretofore neglected tragedy unfolds in the months following the assassination of Abraham Lincoln.

 The movie opens with a meticulous recreation of the murder and the largely bungled conspiracy behind it, deftly capturing the abject horror of the moment and the outcry for vengeance that followed. After all but one of the conspirators are captured or killed, public suspicion is cast on Mary Surratt (Robin Wright) the owner of the boarding house where John Wilkes Booth and his fellows allegedly planned their crimes.

 The War Department, led by the simpering autocrat Edwin Stanton (Kevin Kline), decides that Mary is no longer worthy of her constitutional rights, instead opting to leave her at the mercy of a military tribunal in lieu of a trial by her peers. Her attorney is Frederick Aiken (James McAvoy), a retired Union war hero who initially has nothing but contempt for his Southern-born client.

 Aiken’s attempts to prove Mary’s innocence are decidedly half-hearted until he realizes what a dangerous precedent the trial is setting, one whose effects are still being felt in today’s world of extraordinary rendition and Guantanamo detainees. McAvoy ably portrays his character’s crisis of conscience, and a fine acting ensemble, including Evan Rachel Wood, Tom Wilkinson, Danny Huston and Stephen Root, assist him. Although the effusive courtroom exchanges may wear a bit thin on some audience members, the emotional pay-off and admirable social relevance make Redford’s film an intriguing dramatic exercise well worth an eventual viewing, although one could be forgiven for skipping it in theaters.