In 2001, Robert Hanssen of the FBI was arrested for selling secrets to the Russians. He had apparently been doing so for more than 15 years. It was considered to be the greatest security breach in U.S. history, and was said to have cost the government billions of dollars. Eric O’Neill, a young man striving to become a full FBI agent was assigned to watch Hanssen, and was the person ultimately responsible for bringing Hanssen down.

The movie stars Chris Cooper as Hanssen and Ryan Phillippe as O’Neill. Without giving too much away, I will tell you that Cooper’s performance as an inwardly tortured man was incredible. Hanssen was a devout Catholic, and his religion was incorporated into every aspect of his life. Catholicism also plays a major role in O’Neill’s relationship with Hanssen. But as much as this movie is about Hanssen and his treason, it is also about the relationship between the two men, and O’Neill’s growth as a person. O’Neill ultimately goes through the hardest changes, the more deeply involved in the investigation he becomes.

Cooper is an established talented actor and his performance was excellent but not surprising. Phillippe is an actor that has shown promise, but never really had the vehicle before to truly shine. Now he does. This will be considered Phillippe’s launch into Oscar-caliber acting. He brilliantly embodied the character’s internal conflict as O’Neill continued to form a bond with someone he was told was a traitor. It also had a negative effect on his marriage, which was wonderfully brought out by both Phillippe and Caroline Dhavernas.

The movie also features fantastic performances by Laura Linney as FBI agent Kate Burroughs, Gary Cole and Dennis Haysbert as other agents, and Kathleen Quinlan as Hanssen’s wife, Bonnie. As the credits began to role, I found myself wondering just how much of the movie was true to life, and how much the director and writers had taken Hollywood license with. Usually we do not get a chance to ask these people those questions. This time it was different.

The first thing I noticed during the credits was the real Eric O’Neill had been a consultant for the movie. Wow. But the best part was watching Globe movie critic Ty Burr interview Chris Cooper and writer/director Billy Ray. All three sat at the front of the theater, and after Burr asked his questions the audience got to ask some of their own. Cooper was slightly aloof yet personable, but Ray was very animated as he fielded questions about his methods for both the actors and the script. Ray said that having O’Neill as a consultant lent him important insight into the personal relationship between O’Neill and Hanssen; insight that no one could have had except for those two men. The bond they shared, and O’Neill’s conflict over his ambiguous feelings towards Hanssen is something that was intricately portrayed, and clearly a byproduct of the real O’Neill’s presence. Ray did say he had tried to contact Hanssen in prison, and sent him a list of 15 questions (that was all he was allowed to do), but never heard from Hanssen.

This movie premiered on Feb. 9, so go see it immediately. You can trust that this movie is actually based on the true events it claims to be based on, and features Oscar-worthy performances by its two leading men. It is also an exciting and intense portrayal of a true American spy thriller.