Commerce Secretary Wilbur Ross was annoyed. In May 2017, just a few months after he was confirmed to his Cabinet post, Ross was thinking about the census, the massive survey that goes to every household in the United States once each decade. Ross is charged with overseeing the Census Bureau and on that May morning, he was frustrated at how hard it seemed to be to add a question about citizenship to the 2020 census. “I am mystified why nothing have been done in response to my months old request that we include the citizenship question. Why not?” he wrote to two top aides. A few hours later, Earl Comstock, one of the aides, replied to assure Ross the citizenship question would get into the census. “On the citizenship question, we will get that in place,” Comstock wrote. “We need to work with Justice to get them to request that citizenship be added back as a census question.” In December 2017, seven months later, the Justice Department made the request that Comstock described. In March 2018, Ross announced that after months of taking a ”hard look″ at the issue, he was adding the question to the next census. In January 2019, a federal judge in Manhattan ruled in favor of New York, 16 other states, and a handful of cities and advocacy groups, holding that the Justice Department’s request was a “pretextual” rationale and blocking the administration from adding the citizenship question. Two other federal judges have since ruled that Ross’ action violated the U.S. Constitution’s mandate that the census count all living persons. The Supreme Court is set to hear arguments in Department of Commerce v. New York on Tuesday. The justices have indicated they’ll focus on whether the Trump administration followed proper procedure when adding the question and whether the question violates the enumeration clause of the Constitution.

Bloomberg via Getty Images Commerce Secretary Wilbur Ross said he decided to add a citizenship question to the census after the Justice Department requested it. But there's clear evidence he wanted to add the question long before the request.

The case has significant implications both for the 2020 census and for American life over the next decade. Civil rights, immigration and business groups are all concerned that adding the citizenship question will cause fewer people ― particularly members of immigrant and minority groups ― to respond. An inaccurate count next year would have severe consequences. Census data is used to determine how many seats in Congress each state gets and how $880 billion in annual federal funds are allocated. Businesses rely on the data to plan where they should locate new stores and operations, and local governments use it to plan emergency services. Census data is also the baseline that many pollsters use to ensure their national surveys represent the general public. Some of the strongest evidence in the plaintiffs’ case comes from officials at the Census Bureau. When the bureau’s own experts studied the question at Ross’ request, they advised against it, warning that it would discourage people from responding to the survey and decrease the quality of census data. One Census Bureau analysis found that adding the citizenship question would likely lower the initial self-response rate among households with at least one non-citizen by 5.8%. That translates to more than 2 million households and 6.5 million persons. The Census Bureau, states and advocacy groups are already planning huge campaigns to get as many people to fill out the census forms as possible. But those efforts would be significantly hampered if the citizenship question were ultimately included, said California Attorney General Xavier Becerra (D), who led one of the other legal challenges to the question. Although federal law requires the Census Bureau to keep individual census responses confidential, he said that people may still be worried about answering the question. “Failure is not an option here. It really is not,” Becerra told HuffPost. Adding the question would “bake in a tremendous undercount,” he warned. “Folks can do everything they can to try and get as many people to participate, but it’s going to be overwhelmingly difficult to convince people that it’s in their interest to fill out a form that they have no idea how it will be used.”

Failure is not an option here. It really is not. California Attorney General Xavier Becerra, who opposes adding the citizenship question

The Justice Department is arguing that it needs the question on the decennial survey so that it can better enforce the 1965 Voting Rights Act. Ross has broad authority over administering the census and made a reasonable effort to review the pros and cons of the question before reaching his final decision, government lawyers said in their brief to the Supreme Court. They contend that U.S. District Judge Jesse Furman’s decision in January amounted to a judge impermissibly second-guessing a Cabinet official’s preferred policy choice. Cabinet secretaries do have broad authority to enact policy, but that discretion is “not unbounded,” said Justin Levitt, a former Justice Department official who is now a professor at Loyola Law School in Los Angeles. Although the bar that agencies have to clear to justify implementing a discretionary policy is extremely low, Levitt suggested that Ross may have failed to clear it here. “The reason he gave for his actions was not the real reason. The homework that was done was crumpled up in a ball and thrown away before anyone else actually looked at it,” said Levitt, who joined a friend-of-the-court brief to the Supreme Court arguing the Justice Department does not need a citizenship question to better enforce the Voting Rights Act. President Donald Trump tweeted earlier this month that the 2020 census would be “meaningless” and a waste of money without a citizenship question.

MANDEL NGAN via Getty Images President Donald Trump has said the 2020 census would be "meaningless" without a citizenship question.