A "good" man?

Aristotle states that “The good of man must be the end of the science of Politics” (3). Therefore, the aim of a politician should be to secure the good of a nation. Since politicians generally employ more rhetorical devices on the public than anyone else these days, I always considered Quintillian’s definition of rhetoric as “the art of a good man speaking well” very perplexing due to the inability to pin down a concrete definition of a “good man”. Aristotle even states that man’s definition of ‘the good life’ is generally conceived to be the same thing as ‘being happy’, and that the definition of happiness is fluctuating among men. “Happiness to a sick man is health, and a poor man is wealth, etc”. General consensus would certainly lead one to believe that there are no “good” politicians these days, so therefore according to Quintillian’s definition these men would not be practicing rhetoric. Is Quintillian’s definition of rhetoric a substantial explanation of the practice, or art of rhetoric? Aristotle separates the idea of “good” in politics, and the idea of “good” in many of the arts and sciences, so which definition of “good” would the rhetoric employed by a politician fall under? Amongst all the contradictions in this essay, I feel like Aristotle makes some very profound conclusions, but I can’t seem to find anywhere that he really drives in the definition of a “good” man.