I don't know, just as you don't know, whether Troy Davis is innocent. I do suspect that his conviction would, in this country, be considered unsafe. Not that this, or anything else, matters to the Georgia Board of Pardons who have denied Davis's last appeal for clemency. No-one should be surprised by that. Nevertheless, the case highlights a major problem in criminal trials: eye-witness testimony is often unreliable. According to the University of Virginia's Brandon Garrett:
The federal court that finally reviewed evidence of Davis' innocence agreed "this case centers on eyewitness testimony." Yet that court put to one side the fact that seven of the nine witnesses at the trial have now recanted, and new witnesses have implicated another man. The court did so while failing to carefully examine how eyewitnesses ultimately came to identify Davis as the man who shot a police officer intervening in a fight at a Burger King parking lot. The Troy Davis case—which raises a wide array of flaws in our death penalty system, our post-conviction system, and the politics of criminal justice—is thus also a case about malleability of eyewitness memory and police misconduct.
[...] Police have so utterly contaminated the evidence, and so much has since come to light, that there is not much of the case against him left standing—one could not imagine a jury convicting him today, much less sentencing him to death. Reading through his trial materials, I was reminded time and time again of what I saw when I read trials of the first 250 people exonerated by DNA tests, when researching my book Convicting the Innocent. (There is no physical evidence to test in Davis' case.) Of the 190 DNA exonerees who had been convicted based on eyewitness testimony, nearly all the cases had eyewitnesses who were positive at trial that the defendant was the person they saw. Yet 57 percent of them had not been certain when they first identified the defendant. They became certain only later.
One might want to think that a whole series of eyewitnesses would be much more likely to get it right than just one. Yet in the wrongful conviction cases I examined, 36 percent were misidentified by multiple eyewitnesses, some by as many as three or four or five. Perhaps the best known of those cases is that of Kirk Bloodsworth, the first person exonerated by DNA tests from death row. He was misidentified by five eyewitnesses, and as a result, Maryland now bars death sentences in cases with such weak evidence. We know that eyewitnesses can be influenced by one another—and in several of the innocent exoneration cases I studied, eyewitnesses all viewed photo arrays as a group.
I have a little more faith in the British judicial systems than I do in Georgia's but it's worth observing that Davis was convicted of a crime that death-penalty advocates in Britain would like to see result in executions here as well and that the only way you can be sure of not executing innocents is by not executing anyone. Furthermore, all we know about the unreliability of witness testimony is more evidence that Scots law is right to insist upon corroboration and, therefore, moves to lower the evidentiary bar should be resisted.