Podhoretz makes fun of Brodsky for his remark that if leaders were selected on the basis of their reading experience and not political prowess, the earth would be a better place.
Podhoretz is missing Brodsky's point. Brodsky is simply saying that if one is able to read the classics then conversely one can think.
The more experiences (real and literary) from which a leader can draw, the better the chances for higher level cognitive solutions to problems.
The key to Brodsky's assertion is reading begets thinking; and while aesthetics and literature are the foundation that great leadership should embrace, Brodsky would not limit potential greatness with these two ingredients alone. The psychology of the individual needs to be examined, too.
Assuming that the leader has a healthy psyche, an appreciation of aesthetics and literature is a plus. The fact that Hitler and Stalin were literate yet awful leaders, as Podhoretz points out, is beside the point when their mental health is examined first.