WASHINGTON (Reuters) - U.S. Commerce Secretary Wilbur Ross insisted on Thursday that the plan by the Republican Trump administration to revive a citizenship question on the 2020 census was aimed at bolstering the Voting Rights Act, prompting ridicule from Democrats.

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Critics of the move, now under review by the U.S. Supreme Court, believe including the question will scare immigrants and Latinos into abstaining from the decennial survey, disproportionately under-counting Democratic-leaning states.

Ross testified to the House Committee on Oversight and Government Reform that gathering accurate data on U.S. citizens outweighed any potential reduction in response rates.

“Obtaining complete and accurate information for use in determining citizen age voting populations to enforce the Voting Rights Act is a legitimate government purpose,” he said in written comments submitted beforehand.

“I determined that the importance of that goal outweighed any potential decrease in self-response rates that may result from people violating their legal duty to respond to the decennial census,” he said.

His assertions were mocked by the majority Democrats on the committee, including chairman Elijah Cummings.

“I do not know anyone who believes that the Trump administration is interested in enhancing the Voting Rights Act,” Cummings said, adding: “The administration has done everything in its power to suppress the vote.”

A federal judge blocked the question in January and the Supreme Court will hear oral arguments next month and rule by the end of June. Eighteen states, 15 cities and various civil rights groups are plaintiffs in the case.

Time is of the essence, as the official census forms are due to be printed in the coming months.

The official population count established in the census is used in the allocation of seats in the House of Representatives and the distribution of billions of dollars in federal funds. There has not been a question about citizenship status on the short-form census questionnaire since 1950.

Ross testified that when he got into office in 2017, he began a “deep dive” into all aspects of the survey, including the resources needed to achieve an accurate accounting of the population. Non-citizens comprise an estimated 7 percent of people living in the United States.

He said the request to add the citizenship question came from the Justice Department and denied it was for political purposes.

Republicans, who lost the House to the Democrats in last year’s elections, attempted to shut down the hearing with a motion to adjourn but were voted down.