The United States has been essentially engaged in an ongoing war that most people date from 2001. That war has taken us to Afghanistan, to Iraq, in a lesser way to other countries - Libya, Somalia, Yemen.
James MattisI would consider the principal threats to start with Russia. And it would certainly include any nations that are looking to intimidate nations around their periphery, regional nations nearby them, whether it be with weapons of mass destruction or I would call it unusual, unorthodox means of intimidating them.
James Mattis