Washington • Just off the traffic-snarled George Washington Parkway, over a small footbridge and across from the Lincoln Memorial, lies a natural island unscathed by the development of the nation’s capital. Native Americans fished here. Slaves worked a plantation here. Union troops camped here. And this is where Sally Jewell wants to chat. The Interior Department secretary has one of the most spacious government offices in Washington, a 1,120-square-foot suite with a wraparound balcony and ki...