I find director Alan Parker’s work to be very uneven. While I appreciated his work in films such as Midnight Express, Birdy and The Commitments, he is also able to produce mediocre work, borderline schmaltz… The Life of David Gale is a film with lots of good intentions as far as protesting capital punishment is concerned, yet it suffers from a problematic script and a heavy directorial hand, resulting in unconvincing story, wrapped in melodrama. It is painful to see talent such as the superb Kevin Spacey, Kate Winslet and Laura Linney going to waste.
As to the story’s point – I believe that capital punishment can be protested at one of two very different aspects – justice, and liberal moral.
On the ground of justice – the very slight chance that a man “proved” guilty would turn out, against all odds, innocent after being already executed, exists. It had happened before and it may happen again. Even if it’s only one out of a thousands, it’s still one life unjustifiably taken, making the whole legal system as well as the society that created it, guilty. On this stand alone, capital punishment can and should be protested.
The other stand is completely different. It is liberal moral that claims that an eye for eye is passé, and that, as Gandhi  is quoted in the film itself, “An eye for an eye only ends up making the whole world blind.”
The problem is that the film tries to, unsuccessfully, combine these two almost opposite arguments into one… Here is the issue – if liberal moral is the reason a person should not be executed, than whether the David Gale character is guilty or not is irrelevant, and actually, it would have been better for the moral argument, if he would have been established as guilty without doubt right from the start and throughout the film. If, on the other hand, the argument that he may be innocent is the one used, then the way the plots works itself out in the film, is damaging to the argument (explaining this further to those who didn’t see the film, will result in a plot-spoiler so I will not go further).
So all in all, this film, as mentioned above, does no justice to the point it’s trying to make, and tops it with anything but subtle acting.