His book, The Rise of the Agricultural Welfare State, looks at how farming became one of the most heavily subsidized industries in the U.S., starting about 100 years ago.

Really, the discussion around farm programs begins in the 1920s, which is a period when farmers are really struggling.

And then as we get into the Great Depression and the Dust Bowl, these are years of real hardship in rural areas, low prices, sort of disaster of the Dust Bowl.

And so we start in the 1930s.

providing supports to farmers that usually took the form of the government agreeing to purchase commodities from farmers in order to prop up prices.

And then over the ensuing decades, those programs evolved into a different set of mechanisms to support farm incomes.

Fast forward to today.

For decades, Republicans and Democrats have been able to pass the Farm Bill because both parties got something they wanted from it.