He is a historian and a professor at the University of Chicago, specializing in modern Korean history and contemporary international relations in East Asia. In this instance, I'm not sure why he is considered an expert in American presidents or in Middle Eastern affairs. This is not his area of expertise.
During his talk, he stated that he is not sure why he is so "nervous" but he has been on a "liquid diet."
Criticism
Cumings' scholarship on Korea has been challenged by some academic critics, and in general his work has stirred up more controversy than that of most other historians.Cf. Wikipedia article: Bruce Cumings.
Paul Hollander has argued that Cumings' has a left-wing, pro-North Korea bias. He cites the example of Cumings' discussion of the North Korean gulag system, noting that "in a triumph of selective perception, he manages to interpret the most damning indictment of the North Korean gulag available--The Aquariums of Pyongyang, by Kang Chol-Hwan and Pierre Rigoulot--as providing support for his views of the system. As he sees it, the book is 'interesting and believable' because it is not the 'ghastly tale of totalitarian repression that its original publishers ... meant it to be.' But it is precisely and resoundingly that, as any reader without a soft spot for North Korean tyranny would readily discover. Cumings writes that "conditions were primitive and beatings were frequent [in the camp described in that book] but the inmates also were able to improvise much of their upkeep on their own ... small animals could surreptitiously be caught and cooked." He delicately refrains from mentioning that these small animals were mostly rats, and a regular part of the narrator's diet. That book makes abundantly clear that hunger and malnutrition were endemic; inmates stealing food or trying to escape were executed. Cumings also fails to mention these public executions the inmates were obliged to attend, stressing instead that families were commendably kept together and that "death from starvation was rare." In any event, he suggests, these deprivations are put into the proper perspective by our "longstanding, never-ending gulag full of black men in our prisons"--which should disqualify us from "pointing a finger."
Historian Allan Millett has argued that Cumings' "eagerness to cast American officials and policy in the worst possible light, however, often leads him to confuse chronological cause and effect and to leap to judgments that cannot be supported by the documentation he cites or ignores."
Writing in the Atlantic Monthly, Korea expert B.R. Myers lambasted Cumings and in particular his book North Korea: Another Country. Myers argued that, in the book, "Cumings likens North Korea to Thomas More's Utopia, and this time the wrongheadedness seems downright willful; it's as if he were so tired of being made to look silly by forces beyond his control that he decided to do the job himself."