Less than a week after its signature, the executive order signed by Donald Trump targeting federal employees’ use of official time was challenged in court by a federal employee union.

The American Federation of Government Employees sued the Trump administration May 30, 2018, alleging that executive order overstepped the authorities of the presidency and violated the right to freedom of association guaranteed by the First Amendment.

“Congress passed these laws to guarantee workers a collective voice in resolving workplace issues and improving the services they deliver to the public every day – whether it’s caring for veterans, ensuring our air and water are safe, preventing illegal weapons and drugs from crossing our borders, or helping communities recover from hurricanes and other disasters,” AFGE president J. David Cox Sr. said in a news release on the lawsuit.

Though Trump signed three orders concerning the federal workforce – which make federal employees under investigation easier to fire, call for the renegotiation of union contracts with agencies and limit the amount of time federal employees can spend on union duties – the lawsuit only challenges the third executive order.

Under that order, individual employees may only spend up to 25 percent of their federal work hours on official time, and the average time used per year per bargaining unit employee may only amount to one hour. The order also limits employee ability to use official time to prepare for and pursue grievances against the agency to only those grievances that they are filing on their own behalf.

According to the court document, which was filed in the Washington D.C. District Court, the executive order “impermissibly rewrites” Chapter 71 of the U.S. Code, which covers federal employees’ rights to form or join unions and to collectively bargain with agencies.

As that code is under the jurisdiction of Congress, the suit argues that the White House does not have the authority to impose restrictions on agency execution of it.

Official time has recently been a contentious topic at federal agencies, as some see it as a waste of taxpayer dollars while others see it as a necessary means of ensuring federal employee rights and increasing agency accountability. Still others have argued that a lack of viable data on official time use across federal agencies makes determining the true cost and value of official time near impossible.

Should the AFGE suit be successful, it would void and prevent any action taken under wide swaths of the executive order.