Much has been said about the role of the media in turning public opinion against the American engagement in Vietnam, as images of the war's atrocities were streamed daily on the evening news. Of course, the television coverage didn't cause the war to end immediately, but in America's present engagements in the Afghanistan and Iraq, no doubt with the power of images of war in mind, there has been an effort to manage the video coverage that gets on television screens.

Perhaps in reaction to this, we have now seen a spate of critical documentary pieces on George Bush's 'war on terror', including two Oscar nominees - Taxi to the Dark Side and No End in Sight.

Alex Gibney's Taxi to the Dark Side gets its title from the episode of an Afghan taxi driver, Dilawar, who died in custody after interrogation, torture and beating by the American army. His story is Gibney's departure point (the documentary continues through Abu Ghraib and Guantanamo) for investigating the uses and excuses for torture by the American government.

Highlighting the efforts of two New York Times reporters investigating Dilawar's case, the film is a testimony to the importance (and perhaps the limits) of the free press. Much like in Gibney's previous work Enron: The Smartest Guys in the Room on the Enron scandal, Taxi is more impressive for the appalling, damning material it uncovers than for its filmmaking. Gibney chooses to use post-mortem photographs of Dilawar, naked and bruised. The images are shocking and, against expectation, humanising.

Interestingly, the sympathies of the film also extend to the soldiers who were ultimately charged in the case of Dilawar. They give vivid descriptions of the protocol followed and techniques used, casting an amateurish picture both of themselves and of the army. Gibney assembles a slew of evidence - through the soldiers' accounts, internal memos, legal arguments and statements by former Secretary of Defence Donald Rumsfeld among others - which convincingly connects the culture of abuse with the architects of the 'war on terror'.

Charles Ferguson's No End in Sight (on which Gibney is producer) is a taut, polished and engaging documentary that gives a walk-through of the immediate aftermath of the invasion of Iraq, a period of time which saw massive looting in Baghdad, and Paul Bremer's brief and disastrous tenure as the head of the Coalition Provisional Authority.

As the somewhat clunky tagline 'The Inside Story from the Ultimate Insiders' indicates, No End in Sight relies heavily on talking heads, a trait which is often the bane of documentary films. But the lineup of former military and administrative officials makes for a very engaging commentary on the downward spiral of events in Iraq. It is a gallery of articulate, cool and wronged individuals, who tersely relate the dismissal of their knowledge and experience by their ideologically rigid bosses, who began and persisted with giddy idealism in the face of mounting failures.

There's a growing sense of horror as the events unfold, even as you know the outcome. They don't make spy thrillers this thrilling. Or this maddening.

Taxi to the Dark Side
Director: Alex Gibney.
2007. R. 106 min.
No End in Sight
Director: Charles Ferguson
2007. R. 102 min.