Some would now abjure it altogether, but for more than a century the willingness of the U.S. to employ military might has been an essential element of foreign policy.
Read more on Washington Post: http://www.washingtonpost.com/opinions/robert-kagan-us-needs-a-discussion-on-when-not-whether-to-use-force/2014/07/15/f8bcf116-0b65-11e4-8341-b8072b1e7348_story.html