Well, Larry Solum's great discussion of this colluquy stepped on much I had to say. I commend it. For now, I will post about the progress, which I think is pretty considerable. I did a quick Westlaw check and found that Gerry's book, The Hollow Hope, appears to have been cited over 900 times! The vast majority of these articles are in law reviews, written by law professors. That is more citations than the average law professor receives in a lifetime, and I'd wager that very, very few legal books get so many citations. It could have been cited more, but that's a lot.
As another check, I searched for references to Segal & Spaeth, a fairly iconic source of political science literature on judicial decisionmaking. There were nearly 500 such references (Gerry, you're killing them). In the late 1990s, they received about 20 cites a year, which jumped to 40 cites per year in 2000-2002 and about 60 cites per year since. I doubt this is explained by the fact they keep pumping out research, because the vast majority of these were references to one of their Attitudinal Model books (the first of which was published in 1993). This shows a steadily increasing awareness of the literature, I think, though even today's numbers should be greater.
Lawprofs are not oblivious to the social science research. Economic analysis has pretty much taken over several areas of law that were previously almost entirely doctrinal or philosophical. Economics is not a perfect parallel but it is instructive. How can political science approach this influence? It needs a great champion (I am no Posner). I would consider Lee Epstein's move to Northwestern a very significant step in the right direction, and I expect her to have material influence on lawprofs. The existence of this blog is another significant step. Law schools are increasingly hiring Ph.Ds. There has been steady progress I see, and it is unrealistic to expect an overnight transformation. The glass is far from full, but I see it filling.