Beginning Thursday, American soldiers in Afghanistan will be under orders to back down when they're chasing Taliban fighters whenever they think that civilians might be at risk. Army Gen. Stanley McChrystal, the top commander in Afghanistan, will issue the directive as part of an effort to cut down on civilian casualties, which have enraged the Afghan government and residents. Instead of calling in air support or firing into civilian homes where Taliban fighters have sought refuge, commanders will be instructed to reach out to tribal elders or undertake other efforts to dislodge the fighters. The order is consistent with what...