A majority of voters in a new poll say that a question about U.S. citizenship should be included in the 2020 census, an issue currently before justices on the Supreme Court.

Six in 10 registered voters, 60 percent, in a Hill-HarrisX survey released Tuesday said that the U.S. Census Bureau should ask the citizenship question even if it results in fewer responses. Another 21 percent said the question should not be included, while 19 percent were unsure.

The Trump administration has defended the idea of adding a citizenship inquiry to the census questionnaire mailed to all U.S. households every 10 years after the idea drew backlash when it was first announced by Commerce Secretary Wilbur Ross Wilbur Louis RossTrump admin asks Supreme Court to fast-track excluding people in U.S. illegally from census Trump 'very happy' to allow TikTok to operate in US if security concerns resolved TikTok, WeChat to be banned Sunday from US app stores MORE last year for the 2020 count.

Critics argue that asking census respondents about their citizenship or that of a family member could deter undocumented immigrants from participating in the survey, which is used to help determine allocation of federal funding to different communities.

According to one government estimate, the question could reduce population counts by about 6.5 million people.

Such a reduction could also affect how seats in the U.S. House are divided since seats in the 435-member body are apportioned based on each district's entire population. Democrats have fiercely opposed the Trump administration's push to include the citizenship question in court and in public, accusing Ross of lying about his motives for asking about citizenship.

Supreme Court justices heard arguments in a case about the dispute last week.

Republicans have argued that asking about citizenship status would promote more accurate information about American demographics, while the Trump administration has publicly invoked the Voting Rights Act in defending its push to include the question.

"The American people deserve to know who is in this Country," President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE wrote in a tweet last week.

Despite partisan differences, a majority of voters from all demographics included in the Hill-HarrisX survey said they believed the citizenship question should be included.

White voters overwhelmingly supported the question, with 65 percent in favor and 17 percent opposed. Black respondents favored asking about citizenship by a 53-19 percent margin. Hispanic respondents supported it, 53-28 percent.

More men than women backed adding the question, though a majority of both supported the question, with 54 percent of women and 67 percent of men backing it.

A citizenship question also earned majority support across age groups, though younger respondents were less likely to back it than older ones. Sixty-six percent of voters who were 65 years old or above supported adding the inquiry to the census form while 53 percent of respondents between 18 and 34 did.

Among Republicans, 81 percent supported a citizenship question, as did 54 percent of independents. A plurality of Democrats, 49 percent, said they backed the question, while 33 percent were opposed and 18 percent said they were unsure.

—Matthew Sheffield