Food activists and the industry are looking to a court case between Vermont and a major food distribution association as a bellwether for genetically modified foods.

In May the state legislature voted to require food containing genetically modified organisms (GMOs) to be labeled as such. If the law goes into effect in 2016, Vermont will be the first state to require such labeling. But first it will have to stand up in federal court: The Grocery Manufacturers Association — which is funded by a coalition of companies such as Coca-Cola, Unilever, Starbucks and Monsanto — and three other industry groups sued the state shortly after the law passed.

Now several other states with pending ballot initiatives and legislation that would similarly require GMO labeling are awaiting the district court’s decision. Arguments are tentatively scheduled for mid-December, according to Vermont’s attorney general.

“I know other attorneys general are watching this case closely,” said Vermont Attorney General William Sorrell. “Clearly other states are considering it. This is not a political issue. Most consumers think it’s important.”

If Vermont’s law is shot down in court, it would be a big win for the food industry, which has for years been trying to quash the growing push for GMO labeling. The industry argues that labeling is fearmongering, since the Food and Drug Administration considers food made with GMO essentially the same as non-GMO food.

In Vermont the industry is arguing that the state is trying to unfairly burden the business with its own labeling requirements and superseding federal regulations, which would be in violation of the Constitution’s commerce clause if it interferes with the free flow of food from state to state. The industry is also arguing that such labeling falls under political — as opposed to commercial — speech. Requiring a company to parrot the state’s political speech would be a violation of the First Amendment.

If the court upholds Vermont’s law, the case could have a domino effect across states considering GMO labeling laws. Twenty states have pushed for GMO labeling through legislatures, according to the Center for Food Safety, a pro-labeling group.

Connecticut and Maine have already passed GMO laws, but they include clauses that prevent the laws from being triggered until other states also pass legislation. Connecticut’s law require states with populations totaling more than 20 million to pass similar laws before its takes effect, and Maine’s law is in waiting until five other Northeastern states pass similar laws.

Colorado, California, and Washington have seen unsuccessful ballot initiatives pushing for labeling. Oregon activists have also tried to vote in GMO labeling. A labeling initiative was voted down in 2002, and another attempt in November is still too close to call, with votes being recounted.

Those delays would make Vermont the first state where GMO labeling initiatives would come to fruition, and activists are pinning their hopes on the court case.

“State-based labeling is something that hasn’t been really vetted by the courts,” said Falko Schilling, a consumer protection advocate at Vermont Public Interest Research Group, which is supporting the state with legal help in the case. “There will be more appeals [from the food industry], but this will serve as precedent.”

Grocery Manufacturers Association representatives did not respond to multiple requests for comment for this story, but in a statement on the suit from August wrote, “Vermont’s mandatory GMO labeling law — Act 120 — is a costly and misguided measure that will set the nation on a path toward a 50-state patchwork of GMO labeling policies that do nothing to advance the health and safety of consumers … The First Amendment dictates that when speech is involved, Vermont policymakers cannot merely act as a pass-through for the fads and controversies of the day. It must point to a truly governmental interest, not just a political one.”

Supporters of the lawsuit are confident they can counter the GMA’s claims effectively in court.

“The GMO bills in Vermont, Maine, Oregon — they’re 99 percent the same,” said Will Allen, the owner of Cedar Circle Farm and one of the most prominent anti-GMO organizers in Vermont. “Four states have passed essentially the same law, so it’s not a patchwork. There is a patchwork of laws in dozens of countries, but these companies, they do business all over the world.”

The science on GMOs is controversial. While the FDA considers food containing genetically modified ingredients safe, activist groups contend that not enough is known about GMOs to guarantee there will be no negative long-term effects of ingesting GMO foods. Some studies have found that GMO foods are less nutritional and can cause digestive problems in animals.

But the vast majority of science has found no difference between the safety risks of GMO and non-GMO food. Some scientists have even equated anti-GMO scientists with climate change deniers.

Less controversial is the idea that GMOs are helping produce pesticide-resisitant bugs and herbicide-resistant plants, or superweeds.

Regardless of the science, pro-labelers say it can’t hurt to give consumers more information. The public seems to agree: According to a New York Times poll conducted in 2013, 93 percent of people said foods containing GMOs should be labeled.

The biggest challenge for Vermonters may be proving there’s a governmental interest over a political one. Anti-GMO labelers have pointed to a case in New York in which an ordinance attempted to require family planning service centers that did not offer abortions to say so in their advertising materials. That ordinance was ruled unconstitutional on the grounds that New York couldn’t compel political speech.

But Sorrell and others point out that the government requires labeling of other aspects of food. “It’s a straightforward message about what's in the product,” he said. “We don't think it's an undue burden. We believe in the same way that manufacturers are compelled to list fats and sugars, governmental interest overrides First Amendment protection in this case.”

However the judge rules, the case will likely wind its way to higher courts. Sorrell and his team said they would challenge a defeat and expect the GMA to do the same.

For some activists, that’s the point of the Vermont case. Labeling proponents acknowledge that having 50 states with 50 solutions to GMO labeling would be untenable. But they’re hoping that Vermont will eventually force the Supreme Court to act on GMO labeling for the entire country.

“The GMA will fight us state by state,” said Dave Murphy, the executive director of Food Democracy Now, a national anti-GMO organization. “They’ll probably appeal it up to the Supreme Court. We understand it’s going to eventually be a federal standard.”

Correction: An earlier version of this story incorrectly identified two states that have GMO labeling laws as Maine and New Hampshire. The story has been corrected to reflect that those states are Maine and Connecticut.