The Trump administration is asking the Supreme Court to step in and block two top officials from having to speak under oath in a lawsuit challenging the administration’s decision to add a question about citizenship to the 2020 Census.

In a petition filed Wednesday, the Justice Department asked the high court to prevent Commerce Secretary Wilbur Ross and John Gore, the acting head of DOJ’s Civil Rights Division, from having to sit for depositions in the case. A coalition of activist groups, cities and nearly 20 states, led by New York, say the Trump administration was predisposed to adding the citizenship question, and say it violated federal law by not following the proper procedure for doing so.

Getting information from Ross and Gore is crucial to the lawsuit because Ross, who oversees the Census, has said he added the question at the request of the Justice Department. DOJ said it needed the question, which has not been asked on the decennial survey since 1950, to get better citizenship data so it can better enforce the Voting Rights Act. But documents disclosed as part of the litigation show that Ross wanted to add the citizenship question even before the Justice Department requested it, and that it was Ross who initially approached DOJ officials about making the request.

Leah Millis / Reuters The Trump administration is fighting to block Commerce Secretary Wilbur Ross from having to speak under oath about the decision to add a citizenship question to the 2020 Census.

Critics say adding the citizenship question will depress the response rate among immigrants who fear sharing their immigration status with the Trump administration. Data collected by the Census is strongly protected by federal privacy laws and must be kept confidential.

A lower court in New York has ordered depositions of Ross and Gore, saying they possess unique and relevant information that can’t be obtained from other sources. In its Wednesday filing, the government said the lower court’s ruling was incorrect, and that the case should be evaluated based on an “administrative record” of documents compiled by the government detailing why it made its decision.

“The court thought Secretary Ross’s testimony uniquely vital because he was personally involved in the decision to reinstate a citizenship question and the decision is of great importance to the public,” U.S. Solicitor General Noel Francisco wrote in the brief. “The Secretary’s personal involvement in a significant policy decision is not exceptional, and the importance of the Secretary’s decision in this case does not distinguish it from many other decisions of national importance that Cabinet Secretaries make.”

The information that the government has disclosed in the lawsuit so far has raised significant questions about the decision to add the citizenship query. The documents show Ross and top aides discussing the addition of the citizenship question, and a memo in which the bureau’s top scientist advised against adding it.

Justice Department lawyers have been fighting to block the plaintiffs in the case from gathering information beyond the documents that government officials voluntarily compiled about the decision. However, they have been largely unsuccessful. On Sunday, U.S. District Judge Jesse Furman, the trial judge overseeing the case, said the government’s most recent request was “particularly frivolous — if not outrageous.”

The U.S. Court of Appeals for the 2nd Circuit is also considering whether to block Ross from having to sit for a deposition, but said last week that Gore could be deposed. A trial in the case is scheduled to begin at the start of November.

“The Trump administration has repeatedly tried to block discovery in our suit ― and courts have repeatedly rejected their attempts. You have to wonder what they’re trying to hide,” said Amy Spitalnick, a spokeswoman for New York Attorney General Barbara Underwood (D). “We’ll get to the bottom of how the decision to demand citizenship status was made, as we continue our case to ensure a full and fair Census.”