The U.S. Department of Education is fighting to delay a special education regulation two months after a federal judge found that the agency’s efforts to do so were illegal.

In March, U.S. District Judge Tanya S. Chutkan determined that the Education Department had violated the law in moving to hold off on implementing the “Equity in IDEA” regulations finalized under the Obama administration.

With Chutkan’s decision, what’s known as the “significant disproportionality” rule was to take effect immediately.

The rule in question pertains to an Individuals with Disabilities Education Act requirement that states identify school districts with high rates of students from particular racial or ethnic groups who have disabilities, are placed in restrictive settings or are subject to discipline.

Traditionally, states used varying approaches to flag districts and few were ever called out. The regulation was an attempt by the Obama administration to create a national standard.

Originally, the rule was supposed to take effect in July 2018. But, the Trump administration delayed implementation for two years. That triggered the lawsuit from the Council of Parent Attorneys and Advocates, or COPAA.

In an April posting on its website, the Education Department acknowledged that the rule was in effect as a result of the judge’s decision. But, disability advocates have criticized the Education Department for doing little to enforce it.

When Secretary of Education Betsy DeVos was asked about the rule during an appearance before the House Education and Labor Committee last month, she said only that her agency was “moving toward implementation.”

Now, attorneys for the Education Department have filed a notice indicating that they plan to appeal the judge’s ruling. The filing this week did not say on what grounds the Education Department will pursue its appeal and it’s unclear what the next steps will be in court.

“We hope this is a procedural measure,” COPAA said in a statement about the latest development. “Of course, states are still required to carry out the Equity in IDEA regulations regardless of the legal proceedings and we urge them to come into compliance as required by law.”

The Education Department did not respond to a request for comment about the appeal.