Cognitive dissonance is common in Washington, but some cases truly are exceptional. One is the ritual of the farm bill, when Republicans who campaign on “free markets” whoop through corporate welfare for agriculture interests. But maybe there’s a stroke of sense coming on sugar subsidies.

Republican Rep. Virginia Foxx of North Carolina is making a run at reforming the U.S. sugar program with an amendment to the farm bill that may hit the House floor as soon as this week. This program is arguably the worst farm subsidy, which...