This month’s U.S. Supreme Court hearing of Illinois state employee Mark Janus’s case — questioning the constitutionality of mandatory teachers union dues — could very well lead to a healthier relationship between labor unions and government workers. And what’s more, a growing body of research suggests many states could also help their students in the long-run by making further adjustments to labor union policy.

At stake in the upcoming Janus v. AFSCME case is a 40-year-old precedent that allows governments to force state, municipal, and school district employees to pay union agency fees as part of their jobs. This is problematic when the values and priorities of union leaders and individual members clash. Yet these forced payments are the reality for government workers in 22 states, who could gain the freedom to decide how to spend hundreds of dollars of their own earnings each year.

But what happens when the interests of adults, including education employees, are put before the children’s?

Recent research presented at the 2018 Meeting of the American Economic Association by Cornell University’s Michael Lovenheim and Alexander Willen reveal that forcing school districts to engage in collective bargaining with labor unions ends up harming the students they are supposed to serve. And, unfortunately, the effects are large.

The impact examined by Lovenheim and Willen affects even more states than those whose limits to employee freedom are under scrutiny in the Janus case. Overall, 33 states are considered “duty-to-bargain” states. Laws require school districts and other government bodies to reach a formal binding agreement with a union representing some or all of its employees through the collective bargaining process.

The Cornell study finds that teachers union “duty-to-bargain” laws reduce students’ future earnings by around $800 each year and employment by half an hour per week. And of course, these effects do not only harm the students. The researchers find that collective bargaining reduces earnings nationally by about $200 billion each year.

That is nearly equivalent to the gross domestic product in the entire state of Alabama in 2016. In other words, the effects found in the study have an economic impact on the U.S. economy similar to a halt of all productive activities coming from a state like Alabama.

Lovenheim and Willen provide the first rigorous empirical evidence that the past focus on building union power to protect adult education employee interests has dragged down many of today’s adults. Just as the growing national debt benefits current citizens while forcing future generations to pick up the tab, teachers union bargaining laws steal wealth from future generations because of their damaging effects on educational quality and productivity levels.

Even more disturbing: the Cornell researchers found the largest negative effects for minority groups. Other peer-reviewed analyses have found similar regrettable negative effects of teachers unions on students overall and especially for minority students. But union leaders like the president of the United Teachers of Los Angeles, Alex Caputo-Pearl, continue to claim that their organizations are simply “bargaining for the common good.” Previous studies have shown the effects of more bargaining are more teachers hired and higher salaries for the most senior classroom educators. These raise the costs of public education while harming the next generation financially.

In theory, it is possible that some rules bargained by public officials and private labor groups could help students. In practice, the rules in place have done the opposite.

Even as the nation’s highest court mulls expanding freedom for thousands of government workers, the case against forcing governments to bargain begins to grow.