It might not be the country’s first GMO labeling law, but the bill that Vermont’s legislators sent to Gov. Peter Shumlin yesterday is the only state-level measure with any real teeth. Unlike the laws passed in Maine and Connecticut, it will go into effect in July 2016; neither of those laws can go into effect without the formation of a coalition of states, which could be a long way off. Instead, Vermont is going out on its own with the labeling initiative.

With Shumlin vowing to sign the law, we’re looking at a pretty epic showdown between the some 626,000 Vermonters and the massive food industry. When you consider that Vermont is the No. 1 state in the country for local food and has an active secessionist movement that’s vying to form the Second Vermont Republic, it isn’t an unsurprising fight for the second-smallest state in the union to pick.

That’s the big question about state-level labeling initiatives, especially outside of a populous state such as California, where Proposition 37 failed in 2012. Will Kraft or General Mills change its supply chain top to bottom to avoid having to label its products in such a small market? Or will food companies slap a label on their GMO-containing products, which are legion, and be done with it?

The New York Times suggests another response: “Food companies could simply stop stocking grocery shelves without much lost revenue” because of the small market share Vermonters represent.

More likely, the food industry, in one form or another, will sue Vermont, tying up the issue in the courts. Industry groups are already trying to cut out local measures altogether with a corporate-friendly federal bill.

In the meantime, anti-GMO activists are celebrating what still represents a significant legislative win. “This is an historic day for the people's right to know. It is now very clear that federal labeling of genetically engineered foods is going to happen in the foreseeable future," Andrew Kimbrell, executive director of the Center for Food Safety, said in a statement. The group was involved in writing the legislation.

The law applies to packaged foods sold in a retail environment and to fresh produce. Meat, eggs, and dairy from animals raised on GMO feed would not have to be labeled. The legislation would also bar products containing genetically modified ingredients from being labeled “natural” or “all-natural.”