In the third sentence of the first paragraph the author mentions that war has through the centuries been recognized by international law as a soverign right primarily to

the injury rate in a slaughterhouse is about three times higher than the rate in a typical american factory.

in his "letter from a birmingham jail", martin luther king jr. resort to socrates to highlight his practice of a fair form of civil disobedience and non violence, as a symbol or analogy to back up his interjection outlining the urge of awakening from the "dark depths of prejudice and racism" of society at that time.

here is a little bit of what i learned:

the riots that tore through u. s. various cities in the 1960s. between 1964 and 1971, civil disturbances resulted in large numbers of injuries, deaths, and arrests.   as well as property damage, concentrated in predominantly black areas.  

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a writer of a persuasive essay must include several convincing words ir order to show his position in relation to the situation presented (in favor or against), and thus try to persuade the readers. in the introduction, the word should is usually employed to ask   oppinions ou if somethig is correct or the best thing to do. it can be only an advice, but not a persuasive word, which makes this introduction weak.