BERKELEY, Calif. — TO appreciate the depth of our national political divide, look no further than our Thanksgiving tables. The organic turkeys and farmers’ market produce of coastal urbanites face off against the frozen Butterballs and rich gravies of our rural interior, each side equally contemptuous of the other. Or so it might seem.

But as climate change begins to take its toll on farm country, this geopolitics of “alternative” and “traditional” food is changing. These days, the call to change our food system is coming straight from the heart of red-state America.

I realized this when I went home to Montana to research a book about Timeless Seeds, an organic lentil and heritage grain business that weathered the devastating drought 0f 2012. I interviewed people like Jerry Habets, a barley grower in Conrad, Mont. Three dry years at the turn of the millennium left him desperately searching for answers. Bankrupt, divorced and about to lose his family’s 87-year-old homestead, Mr. Habets tried the Bible. Then he went to a psychic. And then he went organic. That improved his soil so it could store more water.

Tuna McAlpine, a rancher down the road in Valier, made the same decision 10 years earlier, when he stopped using chemicals and converted to a grass-fed livestock system. A libertarian who is concerned that the Republican Party has gotten too soft on guns, he doesn’t want anybody infringing on his constitutional rights. Not the government — and not Monsanto. “I’m a stubborn Scotsman,” he explains.