Rather than just govern the tariffs on goods traded between countries, trade agreements today do much more. They protect intellectual property rights and limit product safety standards, and they establish legal protections for firms that locate abroad. In short, they make it easier for companies to sell goods overseas, Rodrik says. To the extent that American workers will benefit, the thinking goes, they will benefit when businesses’ success with exports trickles down. Trade agreements do little explicitly to improve working conditions, or wages, or workers’ bargaining power within countries. In reality, the effect is often the opposite: “NAFTA’s current rules allow companies to compete based on who can exploit workers or the environment more,” Susan Helper, the former chief economist of the U.S. Department of Commerce under the Obama administration, said, in a Congressional hearing about modernizing NAFTA in July.

Throughout the agreements, it is firms that are the main actors. For example, under today’s trade agreements, firms can challenge government policies that affect their investments under so-called “investor-state dispute settlement” (ISDS) mechanisms. Through these mechanisms, companies have won lawsuits against countries over environmental cleanup and criminal prosecutions, according to Helper, who is also an economics professor at Case Western Reserve University. But no such dispute resolution exists for worker groups or, for that matter, environmental-advocacy organizations. The only remedy for labor groups that think workers are being treated unfairly is to file a complaint with a national administration office, but Helper says these complaints lead to employers getting chastised by government offices, not any sort of requirement that labor practices change.

Even these complaints are rarely filed, according to James J. Brudney, a labor and employment law professor at Fordham University. Labor’s grievances can, under NAFTA, lead to arbitration, but the process of getting to that stage is so difficult that only one labor complaint has reached arbitration in the history of trade deals in the Americas, and labor groups lost because they did not prove the poor labor conditions had affected trade. The number of labor complaints filed declined significantly after 1998, when labor groups realized that NAFTA’s structure was not effective for responding to complaints, Brudney said.

This imbalance is part of the reason why some scholars including Rodrik and Helper suggest that NAFTA renegotiations focus more on workers. For example, Todd Tucker, a fellow at the left-leaning Roosevelt Institute, has proposed that countries agree to let labor take disputes to independent arbitrators, in a similar procedure to the ISDS mechanisms. “You have to have this as an explicit objective, at least of co-equal importance, to simply reducing the cost of doing business and investing across borders,” Rodrik told me. “Ultimately you want to give workers and other segments a much greater voice in the way their economy is managed.”