Seven years after Blackwater contractors killed 14 unarmed Iraqi civilians and injured 17 others in Baghdad’s Nisour Square, a federal jury in the District of Columbia convicted one defendant of murder and three others of manslaughter and weapons charges for the bloodbath. The verdict was announced on Wednesday after 27 days of deliberation...Efforts are underway to fix the accountability gap at the international level as well, largely focused on industry self-regulation...[N]onbinding initiatives are not enough...The U.S. resists labeling its private military contractors mercenaries. But Washington is increasingly relying on paid private gunmen to provide critical services on the battleground and elsewhere, where the risk of lethal errors and the consequences of misconduct are high. Without clear laws, private soldiers will continue to operate in a legal vacuum. The verdict against the Blackwater guards is a small and laudable step toward ending impunity...