A small cadre of experts is quietly crafting a new National Defense Strategy, according to several sources, who say the debate to return the United States to a two-war posture is well underway. The strategy is due to Congress early next year. Defense Secretary Jim Mattis made clear in a Jan. 31 memo the new strategy would support increasing the size of the military by instituting a new "force sizing construct," which will inform decisions on how to best grow...