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 Departments 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. Constitutions 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 theyll focus on whether the Trump administration followed proper procedure when adding the question and whether the question violates the enumeration clause of the Constitution.