Yesterday, the Trump administration took yet another step against working people by announcing that the Department of Labor (DOL) will rescind its “persuader rule,” which would have helped level the playing field for workers by letting them know the source of the anti-union messages they receive during union drives.

Unions help union and nonunion workers in countless ways. They raise wages, make workplaces safer, and close the gender pay gap. Most importantly, unions let workers have their voices heard on the job. The ability of people to join together to negotiate for better working conditions and pay is even more important in an era of forced arbitration, where women who are sexually harassed often cannot get justice in a courtroom and workers who are being cheated out of minimum wage often cannot file class action lawsuits. All workers deserve a voice in their workplaces, and a union is one of the best ways for working people to make sure they are getting treated fairly on the job.

But many employers fight unionization efforts at every turn, by hiring professional anti-union consultants—“persuaders”—to bust their employees’ organizing drives with sophisticated anti-union campaigns. Union-busting firms promise to equip employers with “campaign strategies” and “opposition research,” and produce anti-union videos, websites, posters, buttons, T-shirts, and PowerPoint presentations for employers to deploy against their workers’ unionizing efforts. Employers spend large amounts of money to hire anti-union consultants—sometimes hundreds of thousands of dollars.

So, when a union election campaign is underway, how do workers know the source of the of anti-union campaign materials being thrown at them? Sometimes, union-busting consultants may engage with workers directly to deliver their anti-union presentations, such as in face-to-face meetings. But many times they operate secretly, behind the scenes by creating anti-union flyers, speeches, and videos for management to use to communicate with employees.

Union busters are nothing new, and in 1959 Congress enacted the Labor Management Reporting and Disclosure Act (LMRDA), which (among other things) requires employers and hired consultants to publicly disclose how much money employers paid for anti-union services. Disclosure allows employees in the workplace, like voters in the political arena, to understand the source of the information they are given during the course of a union election campaign.

But for nearly 50 years, employers have been exploiting a loophole in the law that allows them to avoid reporting anti-union work that union avoidance consultants do in secret—robbing workers of the information they need to make informed choices as they pursue their right to organize.

On March 24, 2016, DOL attempted to close that loophole with the persuader rule, which would have required employers and hired consultants to report their behind the scenes anti-union activities. These disclosures would have allowed workers to know whether the messages they hear are coming directly from their employer, or from a paid, third-party consultant operating behind the scenes. The persuader rule also attempted to level the playing field, as unions have much more robust reporting and disclosure requirements under the LMRDA. The rule has not yet been implemented because employer groups tied it up in litigation in federal court, and now, the Trump administration will begin the process of rescinding the rule entirely.

Rescinding the persuader rule is a huge blow to workers’ abilities to negotiate for better treatment on the job by joining a union, and a huge blow to the democratic values of transparency in elections in America’s workplaces. Unions are the best line of defense working people have against unsafe work places, inequality, and wage stagnation. President Trump should be defending working people and their right to join together and negotiate with their employers. Instead, time and time again, he has sided with corporations and their lobbyists.