I watched the entire debate and have a few thoughts about what I saw.
Levinson would like the federal constitutional amending process to be more simple. I get the impression something like willy-nilly ideas getting consideration for inclusion or exclusion. He also believes it is time for a Constitutional Convention. I cannot imagine something much worse than this in the present socio-political climate of the country. At least he was respectful and subdued.
Dershowitz lacks basic intelligence and topical knowledge. He also does what is typical of those on his side of the fence do and that is this. Lacking substantive arguments and the ability to rationally present them, he turns to emotional diatribe. I have seen this my entire life and even in my teenage years with these people. His actions essentially defeat any advancement his own position may have enjoyed since emotional responses automatically lose to intelligent and grounded debate.
Kopel did a good job but tended to get caught up in the "civil rights" argument, in answering to Dershowitz, and fell a little into patronizing that topic. But he certainly did a better job than Dershowitz.
Volokh was the best of the lot. Rational, prepared, not swayed by emotional outpourings, and knowledgeable. He wins among the four of them.
The moderator generally did a very good job of trying to keep things on topic and moving. He was fine.
The audience was very skewed to the left. This should come as no surprise since the debate took place in NYC. One has to wonder what may have been the audience makeup had the debate been held in some other city better representing the core of the nation.
The Second Amendment. This amendment mentions nothing about self defense, about hunting, or about protection against a tyrannical government. It doesn't need to do this. All of these were understood and part of living at the time. No one in their right mind would have raise the idea that self defense was to be constrained accept in the most extreme cases. Or that hunting was to be tightly controlled. Or that the purpose of an armed population was the best insurance against despotism. All of these factors were understood and considered to be the norm. That is why these and other factors are not enumerated in the Second Amendment. And then the issue of guns kept coming up as this relates to this amendment.
Nowhere in the Second Amendment is there a reference to firearms. The word "arms" is used which is a far more encompassing word that guns or firearms. A shovel can be an arm, as can a knife or a spear or a pretty much any other tool put to such use. The Framers knew this and they also knew that an "arm" was a weapon capable of being carried on or about the person. Kopel and Volokh should have put Dershowitz in his place with this factual information and not let him rant on about guns.
Oh well, there goes two hours.