WASHINGTON (Reuters) - U.S. Commerce Secretary Wilbur Ross refused to testify about his department’s 2020 budget before a congressional panel on Wednesday, an act its chairman called one of “stunning disrespect” that left lawmakers facing an empty chair.

FILE PHOTO: U.S. Commerce Secretary Wilbur Ross testifies before a House Oversight and Reform Committee hearing on oversight of the Commerce Department, in Washington, U.S., March 14, 2019. REUTERS/Mary F. Calvert/File Photo

Ross, who was invited to testify at a hearing but instead tried to send aides to a speak on his behalf, has been criticized in the Democratic-controlled House of Representatives over his efforts to include a citizenship question on the 2020 census, an issue now before the U.S. Supreme Court.

Ross said in a statement after the hearing of a House subcommittee on Appropriations: “I am disappointed that these Department of Commerce leaders have not been allowed to discuss their respective budgets for 2020.”

Ross has said he sought the citizenship question in the census to bolster the Voting Rights Act. But Democrats view it as an attempt to discourage immigrants and Latinos from participating in the census, which could lead to an undercount in Democratic-leaning states.

Non-citizens make up an estimated 7 percent of people living in the United States. The citizenship question has not appeared on the list of questions asked of all households since the 1950 census, but has featured since then on questionnaires sent to a smaller subsection of the population.

The U.S. Constitution requires a census to count all residents, including non-citizens, every 10 years. Results are used to draw political boundaries, allocate seats in Congress and distribute roughly $800 billion of federal funds.

The top Republican on the Appropriations subcommittee, Robert Aderholt, said Ross failed to appear out of “concern that this hearing might focus more on political or legal issues than the budget itself. Some have speculated it might turn into a debate over the 2020 census.”

Aderholt noted Ross had sent senior officials to answer questions the panel might have about the Commerce Department’s $12 billion budget request, but the panel’s Democratic chairman, Jose Serrano, ruled that out.

“That will not be happening. This subcommittee invited Secretary Ross to testify and he’s the only one who will be allowed to testify at this hearing,” Serrano told the panel as members sat before an empty witness table marked with Ross’ name.

“The secretary’s actions today show a stunning disrespect for the mechanisms of our democracy,” Serrano added.

It is routine for department heads to field questions from lawmakers each year about their budget requests and other matters. A different House panel, the Committee on Oversight and Reform, voted on Tuesday to authorize a subpoena for documents from Ross about his efforts to include the citizenship question.