In 1970, law professor Joseph Sax proposed a strikingly simple, intuitively appealing approach to environmental protection, namely, that natural resources ought to be regarded as held in common. Because these goods are to be enjoyed by all, the government must assume a trust-like duty not to waste or expend them for the benefit of just a few. Further, the state must take into account future users—later generations who will be harmed if society depletes or damages the environment in irreversible ways. 1