I got this from Mr Cruzing:
"There is a very thought-provoking piece in this month's California Water Law & Policy Reporter entitled "Twenty-Five Years Later, What If The Public Trust Requires That We Kill Fish?" [PDF]. In it, the author explores the idea that the public trust, as defined by the California Supreme Court in the seminal National Audubon case, is informed critically (and flexibly) by "the public interest". As such, the Endangered Species Act, as recently applied by Judge Wanger in the delta smelt case to limit the operation of the Delta pumps to the direct detriment of 23 million Californians, may eventually face a day of reckoning.
It's an interesting thought. Heretofore, the public trust doctrine has been thought of as a holy grail for environmentalists: it protects the environment, at such a supreme level that even the takings clause cannot reach it. And lately, there has been much interest in an extension of the public trust doctrine to fix the Delta, and possibly re-allocate some of California's water resources - see, e.g., the Delta Vision report.
But in the context explored in this article, the public trust cuts the other way. And some have begun to argue that there is a public trust value in other public interests served by California water - for example, a locally-grown food supply. So now it gets interesting, and it does seem self-evident that some of the other public interests protected by the public trust can't be completely excluded by service of environmental interests - for example, water for people to consume, water for people to grow their food supply, and so forth. The posture of the Wanger litigation in the Delta certainly begs that question.
The argument hinges principally on the idea that the ESA must yield to the public trust, where there is a conflict. Some believe that the ESA's commands trump any notion of human costs, and there is support for that in the US Supreme Court's holding in TVA v. Hill. However, there is also a longstanding policy of the federal government's deference to state law in allocation of water, except where explicitly otherwise, and the federal government has not made explicit in the ESA that it is intended to displace the operation of state-law concepts in the allocation of water.
A related concept in California water law, also subject to federal deference, is the idea that all uses of water are constrained by the requirement of "reasonableness". That's found in Article X, section 2 of the California Constitution. Is the use of water to protect delta smelt - required by the ESA, as Judge Wanger has held - "reasonable" insofar as it goes to destroy other uses?
Expect the public trust doctrine, and the reasonable use doctrine, to be litigated in an unexpected direction as California's water picture gets worse and worse!"
[DZ's] Bottom Line: It's hard to predict what's in the public interest, but those who profess to defend it shouldn't expect that it will always match their individual opinions.