SO MANY parts of the nation’s immigration system are rusting, clanking or broken that the situation affords an opportunity for reformers in the Senate: Devise a legislative fix for practically everything and, in the process, forge a broad coalition for a sweeping overhaul that includes legalizing 11 million unauthorized immigrants.

The absurdly dysfunctional agricultural sector is a prime example. Up to two-thirds of the workforce tending to crops and livestock — at least 1 million current workers — are undocumented, up from a third in the mid-1990s. Many are relatively skilled, most have been in the country for a decade or more, and some have moved up to jobs in middle management. Despite their central role in providing the country’s food, they remain subject to harassment, raids and deportation.

Farmers and ranchers have complained about this for years, warning that the shortage of native-born workers willing and able to do agricultural work, along with the threats to migrant labor, would put farmers out of business and shift crop production overseas. Their increasingly dire pronouncements have been met by the usual right-wing rhetoric attacking “amnesty” for illegal workers.