Way back in 1973, when I was a pimply middle schooler living in a Chicago suburb, President Richard M. Nixon signed into law a bill that embodied America’s noblest conservation intentions. The Endangered Species Act set an amazingly ambitious goal: to conserve all of the imperiled plant and animal species in the country.

The act’s authors were fully aware that Americans would have to change their behavior in order to accomplish this goal. They acknowledged that "various species of fish, wildlife and plants … have been rendered extinct as a consequence of economic growth and development untempered by adequate concern and conservation."

But I wonder if they could have foreseen the magnitude of the growth and development we face today. Back in 1973, for example, Nevada had a population of just over 500,000 souls. Today, there are 2.4 million, with demographers predicting another 2 million by 2030. Arizona had 2.1 million people in 1973; today, it is bursting with 5.9 million, and is expected to top 10 million by 2030. This scenario plays out to various degrees throughout the West.

Protecting endangered species and their habitats in an economy tied to population growth — well, conflicts are bound to erupt. So it comes as no surprise that some of our lawmakers — particularly those like California Rep. Richard Pombo, R, who are superglued to the growth machine — want to weaken the Endangered Species Act.

As Tony Davis writes in this issue’s cover story, the crux of the matter is the portion of the law that calls for protecting "critical habitat" for endangered species. A good case can be made that the critical habitat designation process has already broken down under constant political pressure and a steady stream of lawsuits. But broken or not, it still serves an important function: It forces us to think about endangered species in a concrete way. We have to look at the maps, and study the habitat, and consider the consequences of the decisions we make. We have to consider how much land it takes to keep wild creatures alive.

Some of those who are eager to gut the critical habitat provision frankly have no desire to cohabit with thriving wild flora and fauna. To them, aquariums and zoos are just as good as rivers and wildlands — better, in fact, because they don’t compete for habitat with homebuilders and loggers and ranchers. But the Endangered Species Act’s authors valued authentically wild creatures living in native habitat. They wanted their law to "provide a means whereby the ecosystems upon which endangered species depend may be conserved."

That has never been an easy task, and it’s going to keep getting harder. The odds are long that this country can keep its ecosystems intact and healthy while making room for another 80 million or so human beings. We will undoubtedly lose some irreplaceable species, but that is no reason not to try to save what we can. It is no reason to weaken one of the only laws that makes us look at how the way we live affects the other creatures on this planet.