WASHINGTON, DC – The Supreme Court heard arguments Tuesday on whether the 2020 census can ask every person in this country whether they are an American citizen, a question with implications for legislative redistricting, voting rights, and presidential politics.

Article I of the Constitution requires Congress to provide for a nationwide census every ten years. Congress has enacted the Census Act, which specifies broad parameters for the census, then delegates to the U.S. secretary of commerce the authority to fill in the details and then carry out the census, counting every person in America. This function is carried out by the Census Bureau, which is a unit within the U.S. Department of Commerce.

Commerce Secretary Wilbur Ross decided that the 2020 census would restore this question, enabling the government to know out of the 320 million human beings in this nation how many are citizens, and how many are not.

Breitbart News explained earlier this week the many uses of census data, making this a very important legal issue.

U.S. Solicitor General Noel Francisco began his argument to the justices by explaining, “Secretary Ross reinstated a citizenship question that has been asked as part of the census in one form or another for nearly 200 years.”

The Trump administration’s top Supreme Court lawyer was referring to the fact that the census started asking about citizenship in 1820 in the early years of the republic, and kept doing so as recently as 1950. Much of Tuesday’s discussion would compare the census form with the American Community Survey (ACS) – also administered by the Census Bureau – which goes to one in 38 households in America to get statistical sampling. ACS has asked about citizenship since its inception years ago, and no one has raised an objection to that.

Francisco did not get more than one sentence into his opening statement, however, before Justice Sonia Sotomayor aggressively began questioning him, a pattern that would persist through the entire hearing.

“I want to add a citizenship question, I don’t know why, but this is a solution in search of a problem.” Justice Sonia Sotomayor said Ross had thought to himself. “I’ve got to find a problem that fits what I want to do.”

Sotomayor told Francisco that the question violates Section 6(c) of the Census Act, which requires the commerce secretary to use administrative records to gather information instead of asking people on census forms “to the maximum extent possible” while still providing the “timeliness, quality and scope of the statistics [the government] requires.”

“If you really think 6(c) is a problem, then we really cannot ask the citizenship question on the American Community Survey since that is just as subject to 6(c) as the census is,” Francisco explained. When Sotomayor did not readily acknowledge Francisco’s point, he repeated, “6(c) applies to all census instruments, not just the census. It fully applies to the American Community Survey.”

When Sotomayor persisted, saying that she read Section 6(c) as meaning the government could not ask on the census for information available from other sources, Francisco responded that then “you couldn’t ask about sex and age on the census [which it does], since all of that information is all also available in administrative records.”

Justice Ruth Bader Ginsburg said asking the question would depress the count of noncitizens, some of whom are likely not to answer that question. The other liberal justices echoed that concern.

“If you add any particular question onto the census, you’re always trading off information and accuracy,” Francisco responded. He noted the expert assessments that the government would get over 22 million responses to the question at 98 percent accuracy, versus 35 million people for whom the government would have no data, where the government could guess about citizenship, but with an unknown accuracy rate.

“What the secretary concluded was, in the face of uncertainty, he’d rather go with the bird in a hand and ask the question at 98 percent accuracy than an unknown and untested statistical model,” he explained.

Justice Brett Kavanaugh noted that Congress could pass a law requiring or forbidding any question it chooses on the census. “Why doesn’t Congress prohibit the asking of a citizenship question in the same way that Congress has explicitly provided that no one can be compelled to provide religious information?” he asked.

New York Solicitor General Barbara Underwood argued that the three reasons the Trump administration offered for asking about citizenship were unsupported by the administrative record, including the argument that citizenship data would help with enforcement of the Voting Rights Act of 1965 by providing information on CVAP (Citizen Voting Age Population; Francisco explained that courts use census data to determine if racial minorities’ rights are being violated, and that without a census question, both sides in the lawsuits hire experts to offer differing opinions on the CVAP within the state or district where the lawsuit is happening.)

“You think it wouldn’t help voting rights enforcement?” Chief Justice Roberts asked skeptically. “CVAP … is the critical element in voting rights enforcement, and this is getting citizenship information.”

When Justice Samuel Alito referenced the Commerce Department’s getting 98 percent accurate responses to the citizenship question, Underwood tried to convince him that the Census Bureau could develop a statistical model that would be even more accurate, without asking the citizenship question on the census form.

Alito responded incredulously:

If … the secretary knows there’s a 98 percent accuracy rate, and as to the other [option], the Census Bureau says, “We’re going to create a model, and … We can’t give you any statistics, but trust us, it’s going to be more accurate than 98 percent,” is it arbitrary and capricious for the secretary to say, “I’ll go with the 98 percent because that’s a known quantity?”

In what felt like legal ju-jitsu by invoking international norms, Kavanaugh then pressed Underwood to respond to the fact that “The United Nations recommends that countries ask a citizenship question on the census.” She responded that perhaps other nations have not examined how such a question can decrease response rates, or perhaps that problem does not exist in other countries.

Justice Neil Gorsuch quizzed Dale Ho – a lawyer representing other challengers to the census question – how asking the question causes underreporting by people who do not answer the question or do not return the form.

“We have a bunch of states that say that, in fact, the break-off rate … at that question is something like 0.36 percent,” Gorsuch noted. “So that’s very difficult to understand why that question would be the cause of people stopping answering.”

It appeared that the Trump administration had a good day on Tuesday, but that cannot be known for certain until the decision is handed down. A decision is expected in June.

The case is Department of Commerce v. New York, No. 18-966 in the Supreme Court of the United States.

Ken Klukowski is senior legal analyst for Breitbart News. Follow him on Twitter @kenklukowski.