The right to farm hardly seems threatened in Missouri, one of the leading agricultural states, with nearly 100,000 farms producing crops including soybeans, corn and wheat.

But a coalition of state farming groups and major agriculture corporations have spent hundreds of thousands of dollars to take aim at the Humane Society, which led a successful fight in 2010 to regulate inhumane dog-breeding practices in Missouri.

Backers of the amendment are wary of laws that have passed in other states, like California, where voters in 2008 approved roomier living conditions for hens, and Oregon, where a rural county’s ban on genetically modified crops was overwhelmingly passed in May.