Congresswoman Barbara Lee was among Democratic lawmakers begging serious questions on Wednesday after President Donald Trump invoked executive privilege over documents subpoened by Congress regarding the administration's alleged effort to politicize the 2020 census by attempting to insert a citizenship question to the national survey.

"This is about the rule of law. This is about the respect of our institutions. And this is about all of us as a body as a United States Congress and the integrity of the government of the United States." —Rep. Alexandria Ocasio-Cortez (D-NY)"Yet another example of the Trump Admin stonewalling and preventing Congress from exercising our constitutional right of oversight," declared Lee, a progressive Democrat from California, in a tweet. "What is he hiding?"

According to Reuters:

The fight over adding a citizenship question to the census presents high stakes for both Trump’s fellow Republicans and the Democrats, with the 2020 U.S. elections looming. The U.S. Supreme Court is due to rule by the end of this month in the Trump administration’s appeal of a judge’s ruling blocking the addition of the question as a violation of federal law.

The judge's ruling came in a lawsuit by a group of states and immigrant rights organizations arguing that including a citizenship question would frighten immigrants and Latinos from participating in the decennial national population count out of fear of immigration enforcement.

Critics have said Republicans want to engineer a deliberate population undercount in Democratic-leaning areas where many immigrants live in order to gain seats in the House. The census population count is used to allot seats in the House and to guide distribution of billions of dollars of federal funds.

The administration's claim of executive privilege came in the form of a Department of Justice letter sent to House Oversight and Reform Committee Chairman Elijah Cummings (D-Md.) just before a meeting on Wednesday morning where the committee was set to vote on contempt of Congress charges against Attorney General William Barr and Secretary Wilbur Ross for their refusal to share requested documents—first subpoened in April—for oversight purposes.

Like Lee, Cummings asked out loud what the administration had to hide by claiming the privilege.

"This begs the question: what is being hidden?" Cummings asked at the outset of the proceedings. "This does not appear to be an effort to engage in good faith negotiations or accommodations. Instead, it appears to be another example of the administration's blanket defiance of Congress's constitutionally mandated responsibilities."

As Politico reports:

Democrats have accused Ross of lying about how the citizenship question was added to the census, in particular after new evidence emerged recently that highlighted the role of a now-deceased Republican gerrymandering expert who argued that adding such a question to the census would cause congressional districts to be redrawn in ways that help Republicans.

“I want to know why this question was magically added after we have seen that a political operative knew and detailed an intent to intimidate racial and immigrant communities for a partisan purpose," said Rep. Alexandria Ocasio-Cortez (D-N.Y.).

In addition to those comments, Ocasio-Cortez—described as "fired up"—excoriated the Republicans on the committee for failing to defend the process of checks-and-balances and oversight which it is their sworn duty to uphold:

While she said nobody wants to issue subpoenas to other government officials, Ocasio-Cortez said, "We have no choice. This is about the rule of law. This is about the respect of our institutions. And this is about all of us as a body as a United States Congress and the integrity of the government of the United States."