Daniel Solove has a post entitled Judge Posner's Not a Suicide Pact over at Concurring Opinions. Here is a taste:
"I agree with Posner on the point about the living Constitution. Posner's point is that like it or not, the Constitution is already a living Constitution: "So much of the constitutional text is vague or obsolete that a great deal of judicial patchwork is required for the Constitution to remain serviceable more than two centuries after it was written." (p. 19). The problem with Posner's arguments, however, is not in his embracing of pragmatism, balancing, and an evolving Constitution but in the way he goes about his balancing.
Posner argues for judicial restraint because "when in doubt about the actual or likely consequences of a measure, the pragmatic, empiricist judge will be inclined to give the other branches of government their head." (p. 27). Why? It is not self-evident at all that the executive branch has made the most wise decisions on national security throughout history. More importantly, it is not clear why the executive branch is better at balancing civil liberties and national security. If anything, it seems to me that the executive branch might weigh national security too much." (Solove)
(Solum:) I am inclined to disagree with both Solove and Posner about formalism. Posner's frank endorsement of judicial power to amend the constitution should be controversial--something quite odd has happened to legal theory if this kind of extreme legal instrumentalism is considered "within the pale" of acceptable legal argument. So, I am inclined to disagree with much of what he has to say how judges should act.
But if we go along with Posner and Solove, and are evaluating the relative institutional competence of the judiciary and the executive to make all-things-considered policy decisions about national security, then I think it is very hard to make the case for the judiciary as an institution. And if we are to give this power to the judiciary, then for heaven's sake, let's provide judges with adequate national security staff. Perhaps each Supreme Court Justice could be given a national security advisor who would oversee a staff of experts on intelligence policy, military policy, and diplomacy. I should think that with careful planning and a shared pool of area experts, the Court could get by with perhaps two hundred national security clerks. The existing footprint of the Court's building could be preserved with extensive underground additions, and that area could also house the new judicial command bunker from which the Court could operate in the event of attack.
Instapundit rounds up some of the reactions to Judge Posner's book, here. And the Glenn and Helen Show podcast interview with Judge Posner, here.