Late last month, after the CBC reported that the federal government was prepared to agree to allow more American milk into the Canadian market to help complete the Trans-Pacific Partnership (TPP) trade agreement, Marcel Groleau reached out to the New Democrats, Liberals and Bloc Québécois. Groleau is the president of the Union des Producteurs Agricoles (UPA), a Quebec farmers’ union. He was previously an executive with the Dairy Farmers of Canada and president of the Quebec Federation of Milk Producers. His father bought a dairy farm in Thetford Mines, Que., in 1945. Groleau and his brother bought the farm in 1988, and he says the third generation will start taking ownership next year.

A few days after his calls, Groleau was able to put a question to the Prime Minister, at least indirectly. “Mr. Harper, Marcel Groleau asked me to ask you the question,” NDP Leader Tom Mulcair explained from the stage at Roy Thomson Hall in Toronto, where he, Prime Minister Stephen Harper and Liberal Leader Justin Trudeau were debating foreign policy. “The president of the Union of Agricultural Producers. He wants to know if you will fully defend our supply management system. I’ll let you answer.”

“Mr. Mulcair, our position has been clear from the beginning,” the Conservative leader responded. “In all our international negotiations, we always defend the supply management system.”

Groleau admits he was “kind of surprised” to hear his name raised at the leaders’ debate.

That his name was invoked might demonstrate Groleau’s stature and the influence of dairy farmers in Quebec, but also, ultimately, to the strange place of supply management in our political discourse—the obscurely named policy that, in this case, would be raised alongside questions of war, diplomacy, climate change and citizenship.

Supply management is the name given to the systems of tariffs, quotas and price controls that protect the domestic farming industries of dairy, poultry and eggs. Though criticized by economists and fans of the free market—who argue that consumers end up paying more for milk—supply management is supported by every major political party. “Over the years, the political decision has been made [that] this is, pardon the pun, a sacred cow that just can’t be touched because it would be electoral suicide,” says one former government official.

Last week, dairy farmers converged on Parliament Hill to protest the mere possibility that supply management would be significantly affected by TPP negotiations, (Groleau’s UPA helped farmers ensure they had the proper permits.) And the sight of cows in downtown Ottawa and milk running in the streets was the stuff of national news. Any unwelcome move on supply management would likely bring similar scenes. “For sure,” Groleau said in an interview last week, “if the agreement is not good for the dairy farmers, then we will work very hard and we will be very active in the next week.”

Early indications are that the completed Trans-Pacific Partnership might not be met with outrage from the dairy sector. The Canadian government did agree to more access for foreign producers, but is also pledging compensation to domestic farmers. An initial response from the Dairy Farmers of Canada was basically positive.

Three years ago, former Liberal MP Martha Hall Findlay attempted to rebut the idea that ending supply management would come at a substantial political cost. As part of a larger analysis that argued for transitioning out of supply management, she reported that there were “only 13 ridings in Canada with more than 300 dairy farms” (the electoral map has changed since then, but her general point probably still holds). Eight of those ridings, she noted, were won comfortably by the Conservatives, further diminishing the potential impact on the governing party.

But that might oversimplify the political calculus. Of course, in the context of a close election, even a handful of seats could be crucial. And while there may not seem to be a massive number of dairy farmers in Canada—there were 12,010 farms as of 2013—it is not only their votes that could be at stake. “Supply management is important to dairy farmers across Canada, but that’s not all of the people who are affected. Every place in which dairy farming is an integral part of the community and economy relies on stable dairy production and prices, so the impacts of supply management are as much for the communities and the regions as they are for the individuals,” says NDP strategist Brad Lavigne. Explains Groleau: “As producers, we are very involved in our regional economy and regional politics. Each producer has more impact than the average voter, because we buy our supplies from local companies, we sell to local processors, we are at the base of the regional economy.” There might also be the simple symbolic value of protecting the family farm.

Hall Findlay argued that consumers could be rallied by the prospect of cheaper milk; she estimated Canadian families each spend $200 more per year for dairy, eggs and chicken as a result of supply management, with low-income Canadians being hit hardest. Setting aside the debate over price impact, how many votes might actually be won on such a promise? “If you were to run an election on, ‘We’re going to make it so your milk and your cheese and your dairy products are all less expensive by blowing up this system that’s existed for 40 years,’ people would be like, ‘Oh, that’s interesting,’ but it wouldn’t move votes,” suggests the former government official. “It wouldn’t inflame people and make them passionate, as it will if you say to dairy farmers, ‘Your quota, which you’ve borrowed money from the bank against to build your barn, to buy your tractor or to sell for your retirement, that’s going to be worth less now, because we’re going to open your market up to the Americans, Aussies and New Zealanders.’ That’s a lot more of a direct hit on somebody.”

If politicians are supportive of supply management, Groleau says it’s because they have been convinced of the wisdom of the policy.