In the war against terror, the truth is occasionally sacrificed at the altar of perception.

Convince the media and therefore the public that you are winning, and half the battle is already won.

Writer-director Jeffrey Nachmanoff exploits the disparity between fact and illusion in this taut thriller of political intrigue and espionage, creating a horribly plausible scenario for a devastating attack on American soil.

Central to the nightmarish plot is an undercover operative, apparently embedded within a terrorist cell to bring it down from the inside, whose dubious actions continually suggest an ulterior motive.

Like the characters, we’re left in the dark for most of the film whether he is double-crossing the Americans to avenge the murder of his Muslim father in a car bomb, which opens the film.

Rage and grief can corrupt even the purest soul, festering for years before they finally take hold.

A stirring performance from Don Cheadle in the title role muddies the waters, playing up the ambiguities in a character, who is being supplied with actual explosives as part of his covert mission.

Who is conning whom and to what end? Born in Sudan where his early life is marked by tragedy, Samir Horn (Cheadle) is a devout Muslim who aligns himself with the Americans, determined to do his part to heal divisions with the West.

Unbeknownst to his girlfriend Chandra (Archie Panjabi), he goes deep undercover to bring down a cell fronted by Omar (Said Taghmaoui), who he befriends in jail.

They escape confinement and Samir offers his bomb-making expertise as part of a sick and twisted plan to strike fear into the hearts of every American family.

To prove his worth and gain access to the next link in the terrorist chain, Fareed Mansour (Alyy Khan), Samir must detonate a device and kill innocent civilians.

His handler Carter (Jeff Daniels), seemingly the only man who knows that Samir is undercover, urges his man to do whatever is necessary to achieve his goals.

If civilians must die, then so be it.

Meanwhile, FBI agents Roy Clayton (Guy Pearce) and Max Archer (Neal McDonough) begin to investigate Samir as a threat to national security.

As the evidence of a covert plot stacks up, the two men close in on the terrorist cell, jeopardising all of Samir’s hard work.

Traitor maintains a brisk pace after the pyrotechnic-laden opening, cranking up the tension as Samir provides Omar and his minions with the necessary tools to kill hundreds of innocent men, women and children.

Nachmanoff foregoes a barrage of action set pieces in favour of tense conversations between the characters, posing difficult questions about violence as a means to bring down the terrorists.

A couple of twists don’t ring true and the ending signals its sly intentions far too early.

For a change, we are one step ahead of the characters.

• Release Date: Friday 27 March 2009
• Certificate: 12A
• Runtime: 114mins