Finally! Glad to hear it: Seven years after American security contractors killed 14 unarmed Iraqis by firing machine guns and grenades into a Baghdad traffic circle, a jury in Washington on Wednesday convicted all four Blackwater Worldwide guards charged in the incident on at least some of the charges. The verdicts marked a victory for prosecutors, who argued in a 10-week trial that the defendants fired wildly and out-of-control in a botched security operation after one of them falsely claimed to believe the driver of an approaching vehicle was a car bomber. The guards claimed they acted in self-defense and responded appropriately to the car bomb threat and the sound of incoming AK-47 gunfire, their defense said. Overall, defendants were charged with the deaths of 14 Iraqis and the wounding of 17 others at Baghdad’s Nisour Square shortly after noon on Sept.