A former high-ranking U.S. ambassador admitted Friday to illegal foreign lobbying on behalf of Qatar after demanding that prosecutors tell him why a retired four-star general who worked with him on the effort has not been charged. Richard Olson, former ambassador to the United Arab Emirates and Pakistan, pleaded guilty in Washington on federal charges that include improperly helping the Persian Gulf country influence U.S. policy. But Olson has argued he’s entitled to learn why prosecutors aren’t bringing charges for similar conduct by former Marine Gen. John Allen, who led U.S. forces in Afghanistan before being tapped to lead the Brookings Institution. Allen has denied wrongdoing.