President Donald Trump is asserting executive privilege over documents related to the Trump administration’s decision to add a citizenship question to the 2020 census.
The Justice Department notified the chairman of the House oversight committee of the decision in a letter Wednesday.
The committee is set to vote on whether to hold Attorney General William Barr and Commerce Secretary Wilbur Ross in contempt for failing to turn over the subpoenaed documents.
Barr says the president has made a “protective assertion” of executive privilege so the administration can fully review all of the documents.
Democrats fear the question will reduce census participation in immigrant-heavy communities, harming representation and access to federal dollars.
Republicans have criticized the hearings as a waste of time and have called for Democrats to move on.
More must-read stories from Fortune:
—Democrats hold out on USMCA as Trump walks back Mexico tariffs
—The story behind the Baby Trump balloon
—FCC takes major steps toward limiting robocalls and scammers
—Michael Bloomberg pledges $500 million to combat climate change
—Listen to our new audio briefing, Fortune 500 Daily
Get up to speed on your morning commute with Fortune’s CEO Daily newsletter.