Carrying capacity is a relatively simple concept, but estimating the carrying capacity of a region or Earth is complex. Carrying Capacity Network (CCN), a nonprofit organization dedicated to studying and preserving the carrying capacity of the United States, states on its website. Carrying capacity refers to the number of individuals who can be supported without degrading the physical, ecological, social, and cultural environment, that is, without reducing the ability of the environment to sustain the population at the desired quality of life over the long term. Environmentalists will regroup defensively to examine what can be salvaged, what are the root causes of the devastation, and which new strategies hold promise. Environmental protection is, at bottom, habitat protection; this responsibility can be honestly discharged just one way: population stabilization. Environmentalists, facing setbacks in one legislative agenda, have the opportunity to regroup around the real answer. A healthy natural environment is among the quality-of-life indicators that most Americans appear to value.