Gov. Gary Herbert made a lot of friends in Utah when he decided not to sign a water agreement this week with Nevada. The agreement concerned water beneath the Snake Valley, which straddles both states. Officials from both sides had negotiated the pact, which would have allowed Nevada to begin pumping roughly half the available water beneath the valley to supply a growing Las Vegas population.

But while Herbert's decision appears to reflect a strong majority in Utah, it leaves the future unclear.

We have long opposed any attempt by Nevada to withdraw large amounts of water from beneath this fragile and arid desert. Among the most puzzling statements in response to Herbert's decision was the assertion by the Southern Nevada Water Authority that an "overwhelming body of scientific evidence" ought to have persuaded him to sign. In fact, none of the evidence so far has been overwhelming. No one can be certain what would happen to this landscape if the water was significantly drawn down. Nature may not provide second chances in such an environment. Fragile plant species keep soil in place, allowing ranching to thrive. Should those plants die from a lack of water, the environmental effects might be catastrophic.

However, without a signed agreement in place, Nevada may well gain approval to begin pumping from its side anyway. Federal law requires that, absent an agreement between the two states, the U.S. Supreme Court will arbitrate how the water is shared. There is a chance that, should this pumping begin, Utah would be left to rely on courts to protect its interests should such pumping disturb the desert environment. This could be a difficult and uncertain remedy. The state would have to prove it has standing and that any environmental problems in evidence were not the result of some other factors — perhaps difficult to do given the persistent drought in the area.

The agreement at least provided a mechanism for guarding against environmental problems. As soon as such effects became evident, the pumping would have shut down and the problem would have been studied.

The danger, of course, is that by the time environmental degradation becomes apparent, it may be too late to guard against irreversible harm, agreement or not. The most prudent course likely is for humans to leave that desert landscape alone as much as possible, other than allowing it to sustain the few ranchers who reside on it. Las Vegas would do better to search for a more sustainable source of water.

Given Nevada's relentless efforts to begin sucking up this water, that isn't likely to happen. Reaction from that side of the border indicates we may not have heard the last of this matter. Herbert's decision is understandable. It sends a clear message that Utah finds the whole business of Snake Valley pumping offensive. Where both sides go from here is less clear.