From The Wealth of Nations, via Dan Klein:

The laws concerning corn* may every-where be compared to the laws
concerning religion. The people feel themselves so much interested in
what relates either of their subsistence in this life, or to their
happiness in a life to come, that government must yield to their
prejudices, and, in order to preserve the public tranquillity, establish
that system which they approve of. It is upon this account, perhaps,
that we so seldom find a reasonable system established with regard to
either of those two capital objects.

* corn: Any of various cereal plants or grains, especially the principal crop
cultivated in a particular region, such as wheat in England or oats in
Scotland

More from Russ.