Today's San Francisco Chronicle has this op-ed by Boalt Hall Professor Eric Biber. In it, Professor Biber argues that (1) the administrative and economic costs of the ESA are justified by the good that the law achieves (through species preservation), and (2) the Bush Administration Section 7 regulatory changes were bad precisely because they would have exempted from consultation those projects whose effects are currently unknown or speculative.
As for the first point, it is hotly debated whether the economic costs of the ESA are justified. For one thing, it is arguable whether the ESA even achieves its stated purposes; after all, only a dozen or so species that have been listed over the last thirty years have recovered thanks to the ESA. For another, the 1973 Congress could not possibly have contemplated that the ESA would be used to list species like the Delhi sands flower loving fly, or Texas cave bugs, and in the process stop the construction of hospitals and shopping malls.
As for Professor Biber's second point, it is also a very much debated question whether, in the case of ignorance, we should err on the side of species rather than development. Although it's possible that a species could bear a hidden anthropocentric value of exceeding worth, that potential value should be discounted by the likelihood that the species does in fact have that great hidden value. Of course, there's the rub: oftentimes we don't know what the likelihood is, and therefore we can't discount. So, in that instance, do we then "infinitize," as many in the environmental community would have it, or do we discount to zero? The Supreme Court in TVA v. Hill chose the former option, on the grounds that that result was intended by Congress, yet within two years of the decision, Congress legislatively chose the latter. In these hard economic times, if Congress were to vote again, we suspect that the result would likely be the same.