Economist Bryan Caplan, my George Mason colleague and coauthor has some harsh, though not entirely inaccurate, comments about legal scholarship:
At risk of offending my many friends in the legal academy, I think that law is a shockingly phony discipline. Virtually everyone - liberal, conservative, Marxist, libertarian, or whatever - imagines that the law conveniently agrees with what they favor on non-legal grounds. Almost no one admits that many, if not most, laws are so vague that there is no "fact of the matter" about what they mean.
Once in a while, I should add, a law professor has told me this verbatim, and then gone back to arguing about the law. The philosopher in me insists, "If there's no such thing as unicorns, we can't argue about unicorns," but the Great Unicorn Debate never stops.
There is some truth to Bryan's argument. Undoubtedly, legal scholars' views on disputed legal questions correlate closely with their ideologies. The same, of course, can be said for economists' views of disputed economic issues. For example, conservative and libertarian economists are likely to have far more pro-free market views on the causes and consequences of the financial crisis than liberal and radical ones. As I have emphasized on other occasions, most people tend to interpret political information in a highly biased way that privileges their preexisting views and rejects or downplays opposing evidence. Academics are no exception to this trend, and may indeed be more biased than the average citizen because we tend to care more about political ideology than they do. My subjective impression is that the average economist is somewhat better than the average legal scholar about confronting their own biases; but there is wide variation in both groups, and the average difference between them is a matter of degree rather than kind.
Bryan's broader claim that the meaning of law is almost entirely subjective is, I think, greatly overstated. Far from being "vague," most modern statutes are actually extremely detailed and precise. Just peruse a few pages of the U.S. Code if you doubt me. Debates between legal academics make the law seem far more unclear than it really is because they often focus on either the Constitution (an old and on some important points genuinely vague document) or on the few important modern statutes whose meaning is seriously disputed. It's hard to advance an academic career by focusing on the meaning of statutes and constitutional provisions whose meaning isn't disputed by serious commentators. Lay observers like Bryan might understandably be left with the impression that the issues debated by legal scholars are typical of the law as a whole, whereas in fact they are not.
Similarly, as Bryan himself often points out, laypeople tend to think that economics is mostly subjective because public discussion among economists focuses on issues that they disagree on. Thus, Bryan emphasizes, laypeople fail to realize that economists overwhelmingly agree that free trade is better than protectionism, that price controls are harmful, and so on. The same can to some extent be said for legal scholars' interpretation of the law. There is a wide swathe of law (the vast majority, in fact) whose meaning isn't much disputed by experts. But the experts' scholarship and public commentary focuses on questions that generate disagreement. And on those issues, expert opinion (like lay opinion) often breaks down along ideological lines.