Text: He thinks the NEA should subsidize art that will enhance the robustness of the debate and should therefore prefer unorthodox art--though only, of course, if it represents a viewpoint the endowment considers, by virtue of social need and a prior history of exclusion, worthy of its megaphone.
Entailment: It's his belief that the NEA should support art that is unorthodox and yet worthy of special assistance.
Contradiction: He thinks that the NEA should only fund traditional art regardless of any special need or prior exclusion.