Sergio Viera de Mello was the UN's top trouble-shooter, the organisation's "go-to guy" when delicate diplomacy was needed in less than delicate situations.
In a glittering 34-year career, he established a reputation as a dashing maverick who tore up the rulebook to promote peace in the world's conflict zones, and had even been tipped as a future UN Secretary-General.
So his death, in a massive suicide bombing that tore through the UN's headquarters in Iraq in August 2003, killing 22 people, came as a blow to those who knew him and had seen his peculiar blend of pragmatism and idealism at work.
Greg Barker's Oscar-nominated documentary Sergio explores the life, and untimely death, of this charismatic and at times contradictory figure. Viera de Mello bitterly opposed the Iraq War, yet couldn't resist accepting the job as the UN's top envoy in the country after the US-led invasion.
Convinced that the UN could be a force for good in post-Saddam Iraq, he insisted on distancing the organisation from the US administration, even banishing the military vehicle tasked with protecting the UN premises in Baghdad. But despite his best efforts, the UN became a target, and Viera de Mello became a victim.
Sergio tells Viera de Mello's story in unorthodox narrative style, hanging biographical details off a gripping re-enactment of efforts to rescue him as he lay dying in the rubble that fateful day in Baghdad. Barker's skillful weaving of archive footage, high profile interviews and personal reminiscence make for deeply moving cinema.
The film also touches on broader themes. Viera de Mello's final hours were characterised by forewarnings of what would come to be accepted as major failings in the occupation of Iraq. In the re-enactment we learn that the soldiers had none of the right equipment (they were forced to remove bricks using a ladies' handbag and a piece of string), and no clear chain of command. The rescue operation, like much of post-invasion Iraq, was being made up as it went along.
Peppered with in-depth interviews with Viera de Mello's fiancée, the soldiers who tried to save him and the senior political figures behind the invasion, including Condoleeza Rice, Tony Blair and Paul Bremer, Sergio is impressive in its scope, even interviewing an associate of Abu Al Zarqawi, the militant who ordered the attack on the UN.
At times Barker seems to imbue his subject with almost super-heroic qualities, focusing on his remarkable success in guiding East Timor to independence and his daring meetings with the Khmer Rouge deep in the Cambodian jungle to broker the return of refugees.
But the pedestal upon which Viera de Mello is placed has a curious flattening effect on his character -- despite his position at the film's center, he remains an oddly elusive figure throughout.
The motivation behind his work is never fully explored, and a difficult relationship with his wife and sons is alluded to but not tackled head on. Was he a selfless humanitarian who died trying to "save the world," or an absent father who put his ambitions ahead of his family? What finally persuaded him to accept the Iraq job, a post with a limited mandate that he had serious misgivings about and had refused in the first instance?
That Viera de Mello was an extraordinary peacemaker is beyond doubt, and Sergio offers a deeply moving take on his life and death. But because the film examines Viera de Mello's life through the prism of those long, painful hours under the rubble, those seeking a more rounded profile of one of great humanitarians of our time may find that Sergio poses almost as many questions as it answers.