Members of President Donald Trump’s own party called out recent executive orders targeting federal employee unions, due process and official time use as an attempt to undermine existing law.

The executive orders, signed May 25, make it easier for agencies to fire federal employees under investigation for misconduct while calling for the renegotiation of agency contracts with employee unions. They also limit the use of official time, which allows federal employees to conduct union activities such as representing employees in disputes and negotiating contracts with the agency, to no more than 25 percent of an employees work time.

“We are concerned that the recent executive orders embark on a path that will undo many of the long-standing principles protected by law, which establish checks and balances not only in the federal workplace but for the American public,” wrote 21 Republican members of the House in a letter to the president.

“We believe that the three executive orders undermine existing labor laws and we ask that you rescind them.”

The representatives’ open opposition to the executive orders is significant, as House Democrats have already expressed strong opposition to the infringement on the collective bargaining and official time use of federal employees. The new letter marks a solid bipartisan opposition to the new executive orders.

Many of the letter’s signers represent federal employee-dense districts and face reelection in November 2018.

“As members representing a significant number of hard-working federal employees and retirees, we urge you to uphold the current law and long-standing federal labor statutes that protect America’s civil service from discrimination, unfair treatment and sexual harassment,” the representatives wrote.

The legality of the executive orders has already been challenged in court by federal employee unions, and the letter’s assertion that the orders undermine labor laws provides support for that case.

A coalition of 13 unions representing federal employees filed an additional suit June 13, claiming that the three executive orders violate “the rights of government workers to be represented by unions in their workplaces.”

J. David Cox Sr., national president of the American Federation of Government Employees, which filed the May 30 suit, applauded the letter, saying:

“We are heartened by this showing of support for our members and all federal employees. Everyone benefits when management and bargaining unit employees can work together effectively and efficiently, something President Trump’s executive orders undermine. This administration’s attempt to silence the voice of veterans, law enforcement officers and all hardworking federal employees is not just deplorable, it is illegal. The EOs are a direct rebuke to the checks and balances in our Constitution and comes dangerously close to encroaching on the rights of Congress to legislate.”

On June 14, a group of 23 Democratic senators also sent a letter to the president calling for him to rescind the executive orders and adding that they erode whistleblower protections and increase the likelihood of politically-motivated firings.