Republicans may already have paid a political price for the Tea Party's derailment of policies important to rural voters. In the summer of 2012, when the House refused to consider the Senate-passed farm bill, the issue became a point of attack for Democrats who won several red-state Senate races—a subplot of the elections that flew beneath the radar of most Washington observers. And that was before the House spent 2013 delaying farm policy further, leaving agricultural interests intensely frustrated. In 2014, that frustration could hurt Republicans in dozens of House and Senate races.

The farmers' disenchantment with Washington is about more than just a special interest angry that its traditional government assistance is threatened. It's about the deepening divide between rural and urban America. Isolated, shrinking in number, and cast out of the cultural mainstream, rural America now finds itself politically abandoned as well, as the party that once represented its interests is increasingly dominated by a more urban, libertarian, ideological strain.

In the three days I spent talking to dozens of farmers and their representatives at the Farm Bureau convention, a sense of grievance and resentment was a steady undercurrent. Vilsack, who was preceded onstage by an acoustic duo from Tennessee called Pork and Beans who played a song called "Farm Strong," echoed the theme of disconnection in his speech. "My guess is if I took a survey of the folks here today, you might feel that agriculture is not as appreciated as you believe it ought to be," Vilsack said. "I would share that feeling. The reality is, so many Americans are so far removed from where their food comes from. They may be three or four generations removed."

It is only because a small minority of Americans—less than 1 percent—continue to toil at farm work that the rest of the population has the freedom to pursue its dreams elsewhere, Vilsack said. "And folks, that ought to be celebrated," he said, punching the air with an index finger. "The country ought to be reminded of it, and every farmer in this country should be valued, appreciated, and thanked."

Vilsack was followed onstage by Alan Robertson, a member of the cast of the A&E reality show Duck Dynasty. Robertson, a preacher, had previously been distinguished from the rest of the cast by his lack of facial hair, but he had grown a short salt-and-pepper beard for the show's upcoming fifth season. He wore black pants and an untucked blue shirt with a pen in the chest pocket. "You realize that we have generations now that don't understand the concept of home, or family, or faith," he complained. "We got people growing up in huge neighborhoods in metropolitan areas that have no idea what you know, what I know."

Robertson's father, Phil, the show's star, had recently ignited a national debate over the political and cultural divisions between red and blue America with derogatory comments about gays and blacks in GQ. Robertson seemed to be alluding to the controversy when he said, by way of conclusion: "A lot of people are unsure what to do. Watch the show. That supports us." The crowd rose to its feet, applauding, as Robertson walked offstage with his arm raised.