Attorney General William Barr discussing the counting of citizens in the country and the legal issues surrounding that effort, behind him stands Secretary of Commerce Wilbur Ross, in the Rose Garden at the White House.

The House Oversight Committee filed a lawsuit on Tuesday against Attorney General William Barr and Commerce Secretary Wilbur Ross over the Trump officials' refusal to turn over documents related to the administration's decision to add a citizenship question to the 2020 census.

"President Trump and his aides are not above the law," Committee Chairwoman Rep. Carolyn Maloney, D-N.Y., said in a statement. "They cannot be allowed to disregard and degrade the authority of Congress to fulfill our core Constitutional legislative and oversight responsibilities."

The Supreme Court effectively killed the administration's plans to add the question in June, reasoning that the official reason provided was a pretext. The administration argued that the question was needed in order to better enforce certain provisions of the Voting Rights Act.

The committee's lawsuit was filed in federal district court in Washington, D.C. and asks the court to force the two top officials to comply with congressional subpoenas. The Justice Department declined to comment.

A spokesperson for the Commerce Department said in an email that the lawsuit was "fueled by overzealous Oversight Democrats" and "lacks merit."

"Moreover, the Department of Commerce has cooperated in good faith with the Committee," the spokesperson said. The spokesperson said the department made more than 2,000 documents available to the committee and "submitted hundreds of pages of additional documents since the Supreme Court's decision."

The lawsuit follows a vote in June to hold both Barr and Ross in contempt of Congress. At the time, Barr and Ross issued a letter to House Speaker Nancy Pelosi, D-Calif., urging her to postpone the vote because the materials sought by the committee were protected. Trump has asserted that the documents are covered by executive privilege.

In their lawsuit, the Democrats wrote that Barr and Ross "have identified no valid privilege that would justify their refusal to comply."

"Their unlawful withholding of information is injuring the Committee in carrying out two critical constitutional functions: conducting effective oversight of the Executive Branch and its officials, who have provided false testimony to Congress and misled Congress and the American public; and determining whether legislation is necessary, potentially on an emergency basis, to ensure the integrity of the 2020 Census," they wrote.

Earlier this month, Maloney issued a memorandum to the committee that said that the panel's investigation had collected evidence that the administration "may have been trying to stop immigrants from being counted in the Census or in legislative districts, which one Republican operative concluded would be 'advantageous to Republicans and Non-Hispanic Whites.'"

Trump backed down from his efforts to add a citizenship question to the census following the Supreme Court's decision, but said he would press on to obtain the information by other means.

During a July address, Trump said he ordered "every department and agency in the federal government to provide the Department of Commerce with all requested records regarding the number of citizens and non-citizens in our country."

"We will utilize these vast federal databases to gain a full, complete, and accurate count of the non-citizen population, including databases maintained by the Department of Homeland Security and the Social Security Administration," he said.