Besides the labor secretary, President Trump will name countless federal officials responsible for advocating for working people. One of the most important agencies to which Trump will nominate officials is the National Labor Relations Board (NLRB), which protects the rights of private sector employees to join together, with or without a union, to improve their wages and working conditions.

On April 25, POLITICO reported that the Trump administration is considering Minneapolis attorney Doug Seaton to fill a vacancy on the NLRB. Seaton is a well-known union-avoidance consultant, otherwise known as a “persuader” or, more accurately, a union buster.

When workers seek to organize and bargain collectively, employers often hire so-called “persuaders” to orchestrate and roll out time-tested, anti-union campaigns. Union-avoidance consultants do exactly what their job titles describe: they help employers keep their businesses union-free, by either defeating union organizing campaigns or assisting with decertification efforts to unseat an existing union.

Seaton’s firm describes their services this way: “We partner with non-union employers to develop effective and lawful avoidance strategies for maintaining union-free workplaces and counsel them on how to respond to union organizing campaigns.”

Other union-avoidance consultants describe their work in more vivid detail. In 2012, when the Sheet Metal Workers Union began leafletting Buffalo Wild Wings restaurants, the company hired union-avoidance consultants at the Labor Relations Institute, and requested the consultants’ services to “limit the impact of union handbilling activity” and “prevent NLRB [union election] petitions from being filed at all company locations.” As part of the union-avoidance package, the Labor Relations Institute charged $3,000 per consultant per day, and gave Buffalo Wild Wings a set of “ready to launch” talking points and anti-union “flyers, customizable slide presentations, video content, data and other tools.”

And Sparta Solutions—which food service and uniform giant Aramark Corporation hired in 2015 to perform a union “vulnerability audit” of its workforce—boasts that, “SPARTA’s battle-tested methods are proven to work. Let SPARTA show you how not only to win your election, but also teach your staff advanced techniques for union avoidance to ensure your company never goes through a union election again.” All of which, for good measure, is accompanied on Sparta’s website by an image of a soldier in full armor, holding a spear and a shield under the tag line: “Protect and defend your company!”

How do we know this? Because the Department of Labor is required to keep track of it. In 1959, Congress passed the Labor Management Reporting and Disclosure Act (LMRDA), which charged the Office of Labor-Management Standards (OLMS) with enforcing reporting and disclosure requirements for unions, employers, and union-avoidance consultants, who must all file reports under the LMRDA. Employers and hired union-avoidance consultants, for example, are required to file “Persuader Reports,” in which they must disclose their agreements. These reports are publicly available on the OLMS website.

In essence, this law is a transparency law. By requiring employers to disclose that they have hired professional union-avoidance consultants, it allows employees in the labor relations setting, like voters in the political arena, to understand the source of the information they are given during the course of a union election campaign.

And disclosing the amount of money employers spend on anti-union consultants is a key transparency issue—if an employer tells the employees that the business “can’t afford to pay union wages” it is important for the employees to see how much company money is flowing out the back door to the hired union-avoidance firms.

So, how much money do employers spend to keep their employees from joining unions? Despite the statutory reporting requirements, it’s difficult to know because of a loophole in the law.

The LMRDA requires employers and consultants to disclose their union-avoidance agreements, unless the consultant is merely providing the employer with “advice”—a term that was not defined in the statute, and which is exploited by many union-busting consulting firms. The Obama administration’s DOL attempted to close this loophole with the Persuader Rule. When announcing the rule, DOL emphasized how big this loophole is: “Although 71 to 87 percent of employers hire consultants to manage counter-organizing campaigns, the Department has received very few reports on these activities because employers deemed them to fall under the ‘advice’ exemption.” The Persuader Rule is not currently being enforced, though, because the National Federation of Independent Businesses and others have tied it up in litigation in a Texas federal court.

Until the Persuader Rule is implemented, we will have no idea how much companies spend on union busting. But the few persuader reports that are available reveal that companies are spending hundreds of thousands of dollars to fight their employees’ union organizing campaigns (all of this data is publically available in reports on the OLMS website).

You might be surprised to know that many hotels you’ve booked or products in your home came from companies that hire aggressive union-busting firms to prevent their employees from joining a union:

In 2013, Aria Hotel & Resort in Las Vegas hired union-avoidance consultants Balance Incorporated for $195,000

In 2013, Domino’s Pizza paid an anti-union consultant at Action Resources $2,950 per day, for a total of $167,566

In 2015, American Apparel hired the union-avoidance firm Cruz & Associates and paid at total of $462,343

During 2015-2016, New York, New York Hotel & Casino paid union-avoidance consultants at Balance Incorporated $345,182

During 2015-2016, Pier 1 Imports hired union-avoidance consultants at the Labor Relations Institute for $130,331

In 2016, Williams Sonoma paid union-avoidance consultants at Cruz & Associates $150,543

In 2016, Kraft Heinz Foods Corporation hired union-avoidance consultants at The Burke Group for $153,123

Potential NLRB-nominee Doug Seaton has reported at least some of his persuader agreements, totaling receipts of a few thousand dollars. But he benefits from the massive loophole in the reporting requirements that the Persuader Rule would close, so it is difficult to know the full extent of the wealth Seaton has built helping employers defeat their employees’ union organizing drives. If he is formally nominated, Senators should consider asking him whether he has reported all of his dealings in union-avoidance contracts.

But more importantly, by considering Seaton for the NLRB, Trump’s administration is once again breaking his promise to workers that “America’s labor leaders will always find an open door with Donald Trump.” The NLRB is the only federal agency that protects private-sector workers’ right to form a union in their workplace, and is the only agency those workers can turn to for relief if their employer fires them for engaging in union activity.

Nominating a union buster like Seaton to sit as a member of the NLRB will not help protect workers, and will further undermine the strength of collective-bargaining in our country.