Last week, over a hundred Latino workers mounted a wildcat strike at a UPS facility to protest the actions of a racist supervisor. One of their coworkers, Antoine Dangerfield, took out his phone and began filming the walkout, his excitement growing as he realized what he was witnessing. Dangerfield posted the video online, where it quickly netted millions of views. Shortly after, his employer offered Dangerfield $250 to take the video down. Dangerfield explained to them that that’s not how the internet works, and that he couldn’t remove the video. So, they fired him.

This may seem like a bad reason to fire someone, and Dangerfield’s employer may even admit that it was a bad reason to fire him — but it is still probably legal. That’s because the US, for the most part, follows the at-will rule of employment, where an employee can be terminated for good cause, bad cause, or no cause at all. (Montana is the only state that has some form of just-cause rule.)

Though at-will employment is treated as a fundamental feature of American culture and the economy, the rule is not a creation of Congress or any legislatures; it is wholly judge created. The doctrine first appeared in American law in Horace Gray Wood’s 1871 Treatise on the Law of Master and Servant. By the early twentieth century, the rule had become so common in the courts that the Tennessee Supreme Court expressed it in absolute terms, stating, “All may dismiss their employe[e]s at will, be they many or few, for good cause, for no cause or even for cause morally wrong, without being thereby guilty of legal wrong.”

Courts have rationalized at-will employment by arguing that it creates a mutual balance in the employment relationship. As the US Supreme Court noted in 1908, “the right of the employee to quit the service of the employer, for whatever reason, is the same as the right of the employer, for whatever reason, to dispense with the services of such employee.”

But this formulation belies common sense — it completely ignores the power dynamics of the workplace. An employee’s right to quit her job stems from her right to be free from involuntary servitude. An employer may be inconvenienced when an employee up and leaves, but rarely is the whole enterprise put in jeopardy. When an employee is pink-slipped, on the other hand, they lose their livelihoods, their health insurance, and potentially their homes and other assets. Far from creating a balance in the relationship, the at-will rule tilts things toward the employer — who already has outsized power.

There are of course exceptions to the at-will rule, some by law and some by contract. The legal exceptions are those under Title VII, which prohibits firing someone on the basis of their race, color, religion, sex and national origin; some state-level anti-discrimination statutes that include other protected categories; the National Labor Relations Act, which protects workers in their “concerted activities” (anytime when groups of workers band together over workplace issues); whistleblower statutes; and various public policy exceptions, such as unlawful discharge for serving on a jury. The problem with each of these protections is that the employee has to prove that she was terminated for one of these specific illegitimate reasons, rather than the endless legal reasons at the employer’s disposal. And employers have become adept at avoiding liability.

For instance, Antoine Dangerfield may be protected under the National Labor Relations Act if he argues that his filming of the strike was part of the concerted activity. But his employer would likely respond that he wasn’t a “team player,” or he violated some vague rule of civility to justify the firing. And Dangerfield would then have to show that the real reason he was booted from the job was because he was exercising his right to engage in concerted activities. This is a difficult burden, even in the best of cases.

The other major exception to the at-will rule is contractually negotiated just-cause. This largely exists for two groups of employees: unionized workers and high-level executives. A typical feature of collective bargaining agreements is a just-cause provision that only allows the employer to terminate someone for good reason. If an employee feels she was unfairly fired, she can usually resort to grievances and arbitrations to resolve the issue. Similarly, high-level executives often have provisions in their contracts that protect them from being let go without a good reason.

So the deck is clearly stacked against the average worker. At the same, the wildcat strike at UPS shows not only how few rights US workers have, but also the real power that exists in collective action. Antoine Dangerfield’s employer fired him because it could. It is unlikely that the hundred-plus Latino workers that went on strike will lose their jobs. These workers didn’t have a union, and their employer could probably fire all of them with only a slap on the wrist from the National Labor Relations Board. But it won’t do so for a simple reason: they’ve shown that they’re willing to shut the place down. And ultimately, that’s the only way we’ll be able to change US labor law.