The firing of National Labor Relations Board (NLRB) chair Gwynne Wilcox has effectively crippled the watchdog agency, with labor groups warning of widespread impacts for unions across the U.S.

Wilcox was appointed NLRB chair by President Joe Biden in December, for a term that was set to expire in 2028. Shortly after taking office, President Donald Trump tagged NLRB board member Marvin Caplan to fill the role instead, before announcing that he had fired Wilcox and NLRB general counsel Jennifer Abruzzo on January 27. With Wilcox removed from the board, the NLRB now lacks the three-member quorum required to issue decisions, leaving it unable to act on any outstanding investigations into workplace violations, union petitions or unfair labor practices.

In a statement to The Guardian, Wilcox said that she plans to pursue “all legal avenues” to challenge her removal. Under the National Labor Relations Act, the president is only allowed to fire NLRB members for “neglect of duty or malfeasance in office.” A 1935 Supreme Court ruling also limits the president’s authority to removal federal employees who perform legislative or judicial duties, which includes NLRB members.

“President Trump’s firing of an NLRB Member without good cause flies in the face of that precedent and practice and is blatantly unconstitutional,” said Brian Frazelle, deputy chief counsel for the Constitutional Accountability Center, a progressive think tank based out of Washington, D.C.

AFL-CIO president Liz Shuler echoed that sentiment in a January 28 release, claiming that Wilcox’s firing was illegal, and warning of “immediate consequences for working people.”

“These moves will make it easier for bosses to violate the law and trample on workers’ legal rights on the job and fundamental freedom to organize,” she added.

A range of other labor groups have criticized Wilcox’s removal as well, including the National Education Association and Communications Workers of America.