While California endures its worst drought in a century, a small, finger-sized fish with no known redeemable qualities, the delta smelt, has become the centerpiece of extensive litigation. The U.S. Fish and Wildlife Service (FWS) classifies the delta smelt as “threatened,” and since 2008 it has said that large amounts of water should not be pumped out of the delta smelt’s habitat—the wetlands north of San Francisco—and into the state’s drought-stricken central and southern regions.

That “imported” water from northern California has become vital to the state’s important agricultural business, and the FWS’s decision has substantially harmed California’s farms, farm-laborers, and millions of others dependent on the water supply. In short, in order to protect the 3‑inch fish, the state has pumped billions of gallons of water straight into the ocean rather than using it to help California’s struggling farmers.

The farmers, represented by the Pacific Legal Foundation, filed a lawsuit in response to these draconian measures to save the irrelevant fish. The farmers argued that the FWS should not have ignored the harsh financial and human costs of the FWS’s “reasonable and prudent alternatives” to pumping water out of the northern wetlands. The U.S. Court of Appeals for the Ninth Circuit disagreed, holding that the FWS’s decisions deserve deference and that the “FWS is not responsible for balancing the life of the delta smelt against the impact of restrictions” on water pumping. Congress, wrote the court, has already decided that the FWS should protect endangered species “whatever the cost.”

In an attempt to get the Supreme Court to review their case, the farmers argue that the circuit court misread the history of the Endangered Species Act (ESA) and should not have ignored the economic impact of so-called “reasonable and prudent alternatives.” Cato, joining the National Federation of Independent Business, filed a brief in support of their petition. We argue that the ESA has changed since the Supreme Court ruled, in 1978, that species must be protected “whatever the cost.”

The ESA has been amended many times and now commands the FWS to take “into consideration the economic impact” of its proposals. Moreover, the 1978 case that required species to be protected “whatever the cost” has been limited by subsequent decisions.

Finally, we argue that the Ninth Circuit’s decision is in conflict with the Fourth Circuit, which in 2013, vacated an FWS determination because it failed to take into account the economic impact of the reasonable and prudent alternative. This conflict between circuits should be rectified by the Supreme Court, and the ESA should be rightly interpreted as requiring the FWS to take into account the economic impacts of its decisions.

No offense to the delta smelt, but we prefer human beings.

The Supreme Court will decide whether to take the case of Stewart & Jasper Orchards v. Jewell later this year or early in 2015.