A Good American

Many of the supposedly undetectable horrors in the world - child abuse, organised crime, domestic violence - can in fact be combated quite successfully with big data, but there's never enough money in the system to make it happen. A Good American deals with something stranger - a case in which horrors were allowed to happen because, according to its interviewees, the system designed to prevent them was too cheap.

Bill Binney was once hailed as the greatest code breaker in the US. Working for the NSA, he was renowned for his ability to spot patterns in data which was, in the early days, too big for computers to handle. He was particularly good at working out which layers of those patterns were actually significant and could point analysts in useful directions. In the course of his work, he built a program called ThinThread, easy to use and not demanding in terms of processing power. To this day, he maintains that it could have prevented the 9/11 attacks on the Twin Towers. But its use was discontinued.

Although there are any number of accusatory theories out there relating to 9/11, it is, MK ULTRA aside, always easier to believe in incompetence than in Machiavellian schemes. Although Binney's previous involvement in Citizenfour connects him with some of those convinced of the latter, his contribution here - which is substantial - is notably more sober. In fact, that's one of the film's problems. Because whilst Binney is often convincing, the film is very dry. His lengthy monologues, when not much is going on visually, will put off a lot of the people whom he might have hoped to reach.

If you have a love of maths, or even just a love of puzzles, there are parts of this film that you will find compelling. It's easy to see how Binney fell in love with his job and his conversation about this is very engaging. Sadly, that passion is lacking from the parts that really ought to shock.

The public is roughly divided into those who support increasingly 'strong' measures to protect them from terrorists and those who prioritise concerns about personal privacy (often due to wider concerns about the stability of democracy). With these two understandable positions often treated as polar opposites, it's nice to see a film whose subjects are concerned about both and are interested in finding ways around apparent clashes. Crucially, ThinThread would - we are told - have let Binney see the connections and patterns necessary to identify terrorist plots whilst keeping the content of email messages and so on encrypted, but as with so many well intentioned schemes, it fell into the hands of people who found it more to their tastes to take those safeguards out. Perhaps our hero should have been a watchmaker.

The notable thing here is that we only have our hero's word for this, and the words of a handful of supporters. The case made by the film would have been much stronger if these were subjected to scrutiny. No serious challenge is made, either by others connected with the NSA (who apparently refused to cooperate) or by third parties. Viewers are asked to accept it all at face value, which rather goes against the spirit of a story about suspicion and the importance of thinking for oneself. What Binney says may well be true, but a fair bit of it is speculation, especially when it comes to the motives of others. The viewer, ultimately, faces the task of sifting through a great deal of talk to try and identify what is both significant and reliable.