as high as an elephant's eye

While the staple crop, one of the more domineering and hardy among agriculture, perfected by millennia of stewardship, presents nothing objectionable in itself—and quite the opposite if tended responsibly, corn management and corn policy (native to America but an invasive species) has grown into something untenable and potentially disastrous.
Without even addressing the myopic decision to tinker with the genetics of our food, the way corn is grown, the harvest almost exclusively diverted into feeding animals and automobiles and producing food additives and fillers, like the dreaded corn-syrup. Not counting acres and acres destined to become ethanol, biodegradable plastics or base ingredients for something more chemical and refined than flour or meal, this second-hand nutrition, feeding livestock rather than eating what we've reaped ourselves, reduces the efficiency of the land by some eighty-percent and more. Of course, through subsidies at the expense of the tax-payer and at the expense of the environment, creating vast tracks of monocultures and demanding more and more resources and land be used to satisfy exponential appetites with nascent returns, are eventually articulated as something more profitable to some, which is also something not valued-added for all.