This paragraph in Eli Lehrer's latest at the Weekly Standard seems quite useful to how we should think of the farm subsidy debate:

Whatever function they once served, America’s producer-side farm subsidies no longer have any valid public purpose. The much-romanticized family farm is, for all intents and purposes, dead: The number of farms producing enough income to support a family (more than $100,000 in gross revenues) has declined every year since World War II. As of 2012, only about 400,000 commercially viable farms—less than three-tenths of 1 percent of all households—exist in the United States. The great bulk of subsidies flow—directly or indirectly—to wealthy people and agribusiness. The Environmental Working Group found that 26 businesses got over $1 million each in crop insurance premium subsidies during 2011 alone. Furthermore, many of the most promising sectors of the agricultural economy—boutique organic farms and wineries—are also those that receive the least support from the government.