Actually, on second thought, I think he's already warned us what he intended to do. His comment about not making our case for us indicates that he intends to proceed like a lawyer or a pol: at the intellectual level of a seminar grad student and the moral level of a used-car salesman.
I think we err in engaging him in the first place, if he has told us he's just going to spew.
I concur with the latter but in the case of the former I think you give him two much credit...unless, of course, you are referring to the modern day seminar environment in which every single class has that one student who is both arrogant and ignorant. The type I refer to is normally an "affirmative action case," so to speak, more often than not female (no offense to women in general - just an observation), and tends to stick out in the class as the one person who simply doesn't belong in any college level educational environment much less at an advanced level but is nevertheless there. I remember those types well only a few years back and with the rise/return of affirmative action after O'Conner's Michigan case copout I can only suspect that it's worse now. They usually sit front and center in the class and end up consuming roughly a quarter of the lecture time by asking inane, stupid, completely unnecessary, and oftentimes combatively hostile questions that seldom have anything to do with the lecture material and almost always serve as a disguise for what is in reality an intellectually unsupported personal opinion drawn out over several qualifying paragraphs before being phrased in the form of a question. Assuming he was ever in college, I suspect that el capitan was his classroom's version of this type of individual in more cases than the average student.