Because the Endangered Species Act is concerned with the effects of human activities on the natural environment, the law covers a lot of ground, both real and figurative. It can regulate large geographic areas of desert, mountains and forests, as well as have wide legal implications affecting a range of human activities: political, social, economic, and cultural. ESA's enforcement, however, is broadest, most complicated and far-reaching when applied to habitat and species that rely on water. As a result, the law has special significance in Arizona and the West. Here historical, geological and political factors contribute to make water a highly charged public policy issue. ESA at times adds volatility to the issues.