Style and tone can be analyzed in a writer's use of facts
diction
handwriting
philosophy

kennedy creates personal credibility by saying he is more than fit to lead. he talks about the sixty day period that he constructed administration, and says based on that he will be an acceptable leader.

jfk has a great reputation as an american citizen. he fought in wwii, and earned the navy and marine corps medal. he saved several men on his pt-109 patrol torpedo boat after an attack by the japanese navy. he also served in congress for the 11th congressional district for massachusetts, and served three terms in the house of representatives.

explanation:

that is true because that is something they fulfill for their work.