It happened again. Last month, on Veterans’ Day, as many as forty high school students in Richfield, Minnesota were served a hot lunch, then had it taken away and thrown out. Their crime: incurring $15 or more in unpaid school-lunch debt.

While Richfield School District eventually apologized, it did so for the wrong reason. As district officials told the local news, the proper procedure was to prevent those children from entering the lunch line in the first place. Apparently, denying food to schoolchildren wasn’t something for which they needed to express contrition.

To be fair, the embarrassed students weren’t denied all sustenance — they got a cold lunch instead. But it was yet another instance of “lunch shaming,” a grotesque American phenomenon where kids unable to pay for their lunch are in some way branded or marked as debtors. In the last few years, we’ve seen lunch shaming all across the country: in Alabama, where students had “I need lunch money” stamped on their arms; in Rhode Island, where a school district hired a debt-collection agency to pursue students who hadn’t paid for lunch, and in Utah, where, as in Minnesota, students were served a lunch and then had it seized from them and thrown out, uneaten.

Several states have taken action to rectify the problem. California recently implemented a law that bans stigmatizing students with lunch debt, and New Mexico has passed a similar measure. At the federal level, Minnesota senator Tina Smith and representative Ilhan Omar have introduced comparable legislation.

It’s good to see legislators getting on board with the notion that we shouldn’t shame children for being too poor to buy lunch. But surely that elides the real issue: why is a student’s access to a decent lunch in any way contingent upon their ability to pay for it? A good meal is as essential to a student’s education as textbooks or pencils. Many students do qualify for a free or reduced-cost lunch under current guidelines, but not all parents apply for the program, and the Trump administration is looking to cut that program substantially.

Forget for a moment whether they get a hot or a cold lunch. How many students aren’t approaching the lunch line at all because they’re ashamed of their inability to pay for it? If the answer is any number more than zero, it’s a moral failure of the highest magnitude.

America’s education system has enough challenges. Lunch shouldn’t be one of them.

Making school lunch free would hardly break the bank. In the case of the Richfield School District, “Food Service” accounts for just $2.78 million out of a $107 million annual budget.

But why wait? In every school district where food service personnel are unionized, unions could advise their members to provide every student a hot lunch who wants one, regardless of their ability to pay. If school districts ordered employees to keep track of students unable to pay, unions could encourage their members to refuse. Through conscious acts of insubordination, unions could make lunch free for millions of schoolkids. In schools where workers don’t have a union, they could still band together to do the same thing — so long as workers are united, they still have the same strength as if they had a contract.

Now, let me be clear. I’m not calling for individual wildcat action or rash, unplanned, group actions. Instead, I’m encouraging education unions to have deep, honest, and open conversations with their members. Who has seen kids hungry at school? Who has had to say no to a starving kid because of a draconian policy? Who has witnessed kids being mocked or bullied because of their poverty? Who has dipped into their own pocket to buy lunch for a kid who didn’t have anything that day? Ask that last question in any room full of educators, and I’d be stunned if at least half didn’t raise their hand.

People who work for schools don’t do so to get rich. They do so because they believe in something, and it has to hurt workers when they’re told to deny food to hungry children.

Education unions are at the forefront of the emerging strategy dubbed “Bargaining for the Common Good.” The recent Chicago Teachers Union / SEIU Local 73 strike, for example, centered issues of fair housing and special-education needs, not just wages and benefits. But unions can support the common good away from the bargaining table, too.

If a union representing food service workers announced that its members would no longer keep track of which students could or couldn’t foot the bill for meals, and would serve meals to any student who asked, we can be sure school districts would try to stop it. As a practical matter, however, there typically aren’t enough nonunion school personnel to monitor lunch lines, and so school districts would be faced with a dilemma: let the practice go forward, or try to discipline employees whose only infraction is feeding hungry children.

As a grievance case, this is a loser for workers; as a political argument, it is much stronger. One of the key aims of civil disobedience is forcing the public to confront a moral crisis. Rebuking employees for feeding the hungry is a moral crisis. How long would principals and superintendents stick to their policies in the face of a united union membership? Which elected school-board members are going to run for reelection on a “Starve Poor Kids” platform?

This won’t be so simple everywhere. In many public school districts, food service work has been outsourced to nonunion, for-profit companies. And in many states, education workers don’t have the right to form unions. Those workers may understandably be more reluctant to act. Unions would need to be creative and find ways to apply moral pressure in especially anti-labor environments. But in strong union states — New York, California, Massachusetts, Illinois, Oregon, Minnesota, and so on — members should begin talking now about how they can push their school districts to do the right thing and feed children.

When I took part in my first civil disobedience action to win union rights for graduate workers at the University of Illinois in 2000, we were advised by a labor lawyer: “organize, and the law will follow.” Food service unions should follow the same dictum.

Denying students a hot lunch is a moral outrage. Organized labor action can make free school meals for all a reality.