A driver monitors corn being loaded into a truck on a farm near Walnut, Ill., in June. (Daniel Acker/Bloomberg News)

ACCORDING TO the old saw, anyone who wishes to maintain respect for sausages and laws should not see how either are made. Congress has just finished validating that aphorism by engaging in the sorry every-five-years exercise known as drafting a farm bill. This mishmash of subsidies and regulations purports to protect U.S. agriculture, not just from the vagaries of pests, crop diseases and weather but also from the ups and downs of the free market itself.

Inevitably, the farm bill showers benefits on well-to-do business owners who don’t need or deserve taxpayer help under the cover of deliberately obscure terms such as “federal milk marketing orders” and “base acreage.” It’s true that farm income has dropped in each of the past four years because of falling commodity prices, but Congress showered agribusiness with taxpayer largesse when incomes reached all-time highs a half-decade ago, too. Clumsy ma­nipu­la­tion by government probably exacerbates market swings.

Where is it written that this one sector deserves federally guaranteed profitability? You will hear a lot about the need for food security, but it’s mostly nonsense: A mere 6.3 percent of Americans’ consumer expenditures were on food consumed at home in 2016, according to the Agriculture Department . This was easily the lowest percentage in the world, as it has been for many years. Even in the wildly unlikely event it doubled, we’d still be better off than developed countries such as Sweden and France. If Congress really wanted to help farmers, it would do something to stop President Trump’s trade war, which has provoked retaliatory tariffs by China and others against U.S. farm exports.

This year’s process has introduced a new level of ugliness to this inherently unlovely law. The House version of the farm bill, passed with Republican votes only, would add a work requirement to the government’s largest food aid program for the poor, the Supplemental Nutrition Assistance Program, or SNAP. Helping poor people buy groceries is the main way the farm bill actually enhances food security; for decades, linking SNAP to farm subsidies in a single bill has been the price of urban lawmakers’ support for rural corporate welfare. Mr. Trump applauded the measure, which would make most adult SNAP recipients (up to 7 million people) spend 20 hours per week either working or participating in a state-run training program as a condition of receiving benefits, which at present average $125 per month to 42.3 million Americans.

Democratic representatives, mostly from urban America, and several Republicans, too, recoiled. Correctly, they cited the bill’s insufficient funding for training programs, as well as the added paperwork and administrative burden. They might also have noted the bill’s juxtaposition of tougher eligibility criteria for the poor with continued sugar price supports for agribusinesses in the South and Midwest.

A large bipartisan majority of the Senate rejected the work requirement, which may mean that it can’t survive the conference committee. The mere fact that it has gotten this far, however, tells you something about farm-bill politics in general and the priorities of the Republican House in particular.