SpaceX, Starbucks, Amazon, and Trader Joe’s have all taken swipes at the NLRB as of late. SpaceX has led the charge with an “I know you are but what am I” approach to allegations of union-busting by claiming the agency is unconstitutional. 

Jennifer Abruzzo, acting general counsel of the NLRB as appointed by President Joe Biden, isn’t standing down to these corporate entities, and called out their legal tactics during a panel hosted by the Roosevelt Institute last week.

“A growing number of deep-pocket, low-road employers are jumping on the bandwagon, seeking preliminary injunctions in courts, solely to slow [us] down or prevent us from engaging in our enforcement actions against them because they have the money to do so,” she said.

These legal tactics are distractions to “divert attention away from the fact that they are actually lawbreakers who need to be held accountable in a timely manner,” she added.

Abruzzo described a back-and-forth that’s not unlike a David and Goliath story, if Goliath was simply trying to run out the clock and leave David high and dry.

The NLRB isn’t deterred, though, despite limited resources and a deluge of unfair labor practice filings amid heightened strike activity. “There is no way we’re going to succumb,” Abruzzo said, adding that the board will continue to call out companies where it sees fit—even among challenges to its very existence. 

The main challenger of the NLRB, SpaceX, began its campaign against the federal branch earlier this year. Just one day after the NLRB issued a complaint against the astronautics company on Jan. 3, SpaceX sued the board in the Southern District of Texas, asserting that the institution’s structure was unconstitutional. A judge subsequently opened the SpaceX hearing in March, with a case expected to be heard starting in May. 

Amazon, Starbucks and Trader Joe’s followed suit in the company’s crusade against the almost 90-year-old institution, Abruzzo said Friday. “These esoteric legal arguments came about, why? Because we dared to issue a complaint against SpaceX after it unlawfully fired eight workers for speaking up about their workplace concerns,” she said. 

SpaceX’s pushback and suing of the organization “seems much more an ideological debate than how most employers handle it,” Matthew Bodie, a labor law professor at the University of Minnesota who was a previous field attorney at the NLRB, told Fortune’s Jessica Mathews this past March. “It just seems like more of a crusade, almost, than a rational economic response to litigation.” 

While SpaceX is leading the charge, other large employers have eagerly taken up the same argument. Trader Joe’s argued that the board, in its current form, shouldn’t exist during a hearing in January over alleged unfair treatment of workers at its Hadley, Mass., store—its first in the nation to unionize.  

“The National Labor Relations Act as interpreted and/or applied in this matter, including but not limited to the structure and organization of the the National Labor Relations Act Board and the Agency’s administrative law judges is unconstitutional,” Trader Joe’s attorney, Christopher Murphy, said in January, according to a transcript first obtained by HuffPost. 

“I’m certainly not going to be ruling on my own constitutionality anytime soon,” quipped Administrative Law Judge Charles Muhl. “You’ll have to take that up with the Board and with the federal courts.”

Trader Joe’s—another of the companies taking aim at the NLRB—told Fortune the company “has not filed or joined any lawsuit that challenges the constitutionality of the NLRB’s administrative law judge system or seeks to dismantle any aspect of the NLRB.” It added that its statement during the January hearing was “an affirmative defense,” which “was not an argument; it was an opportunity to preserve all of our legal rights under the law.”

Amazon raised a similar argument in a case regarding the only Amazon warehouse to successfully unionize, in Staten Island, N.Y. Starbucks did the same in a post-hearing brief about some of its stores. Starbucks, however, has now distanced itself from Elon Musk’s raging brainchild. “Starbucks has not joined a lawsuit against the NLRB questioning its constitutionality or initiated similar litigation against the NLRB,” the company told Fortune, linking to a statement. As of March, the coffee conglomerate has 741 open or settled NLRB cases, according to the Economic Policy Institute—although the coffee chain recently reversed itself and pledged to negotiate with its unionized workers. 

Amazon did not respond to Fortune’s request for comment.

Legalese aside, these major employers have been part of the ranks of companies answering charges of labor complaints by pointing the finger back at the NLRB. Whether or not they have called the NLRB unconstitutional or simply implied it, these employers are joining the Republican-backed charge against one of the only federal safeguards of workers’ rights.

But these corporate titans’ crusade isn’t meeting meek soldiers. “We are not going to stop despite these challenges,” said Abruzzo, noting that the NLRB is the only federal agency guarding the rights of workers to unionize. During a time of workers’ discontent, billion-dollar companies are seemingly attempting to make one of the few checks to their power go broke. 

“It seems to me they would rather spend their money initiating court litigation rather than improving their workers’ lives and their own workplace operations,” said Abruzzo. She added the main goal is to “divert our scarce resources away from protecting workers’ rights to organize and to fight for recognition and respect for the value that they add to their employers’ operations. And that is not going to happen.”

The NLRB isn’t just twiddling its thumbs until it gets its day in court; rather, it appears to be fueled more than ever to tackle these companies and workplace violations. But Abruzzo conceded the companies’ efforts to draw attention to the NLRB are having an effect. 

“Frankly, that strategy is working,” she said. “There’s a lot of public reporting about the challenges as opposed to the law breaking.”