The first-ever attack by Somali militant group al Shabaab on U.S. military forces in Kenya portends an intensified focus by the group on American targets and potentially greater insecurity in East Africa. Jihadist militants from the group stormed Camp Simba on Jan. 5, killing a U.S. service member and two contractors and destroying several aircraft and helicopters. Al Shabaab's first-ever attack on a U.S. military installation in Somalia occurred just months ago, and it has previously killed Americans in attacks on soft targets in Kenya....