India, June 8 -- West Bengal's new government insists it is merely enforcing an old law. Legally, that is true. Politically, economically, and socially, it is far more complicated.

The controversy over the enforcement of the West Bengal Animal Slaughter Control Act, 1950, just before Eid al-Adha has been presented as a debate about faith. To categorically deny it would be untrue. But it is also a debate about rural economics, agricultural realities, and the unintended consequences of laws frozen in another era.

The 1950 Act permits the slaughter only of cattle certified as over fourteen years of age or permanently incapacitated. In 1950, when India had barely anything, and agriculture depended on bullocks for ploughing, transport, and ...