After world war 2, drug abuse rose. Evidence of this was seen in the Vietnam war as many soldiers were under the influence of opium as heroin ran rampant throughout US troops in Vietnam. They could not come home unless they passed a drug test, which often times made them stay sober for up to a week. This is just an example.
Using the word "sinew" suggests that there are many components of what make peace work, and it implies that we as people must know how to be peaceful by cooperating with each other.
