(CNN) Arguments in the trial over the Commerce Department's decision to reintroduce a question about citizenship in the 2020 census concluded in federal court on Tuesday amid fresh pleas from the Justice Department to the US Supreme Court to delay the case.
Numerous state attorneys general and civil rights organizations brought the challenge alleging a political motive behind the decision to reinstate the question. Critics of the citizenship question argue that its inclusion will discourage noncitizens from filling out their forms, which could mean segments of the US population are underrepresented.
In the weeks leading up to and during the trial, the Justice Department asked the Supreme Court to step in and delay the trial because of a dispute over the scope of discovery.
The most recent request came in the form of a letter from Solicitor General Noel Francisco on Monday night, just hours before closing arguments were slated to begin in downtown Manhattan. The Supreme Court has already said it will hear a portion of the case in February.
At the heart of the case is how the reintroduction of the citizenship question to the 2020 census will affect the data the government gathers.
The census is a crucial document for determining how federal funds are allocated and how congressional districts are drawn for the following 10-year period. It is meant to account for everyone living in the United States, not just US citizens. The citizenship question has not been asked of all recipients since 1950.
The main witness in the case, Census Bureau Chief Scientist Dr. John Abowd, testified during the trial that adding the citizenship question to the census would likely not result in an undercount of the population overall, because the bureau has a follow-up process where it will visit the houses of individuals who have not returned their forms.
However, Abowd noted that the addition of the question would likely "decrease self-response and increase cost."
The government argued that because there wouldn't be an undercount of the population, there would be no issue with including the question. It also noted that the question has been used in a different survey, the annual American Community Survey.
The challengers argued that even though the overall population count might be accurate, there would be an issue with the quality of the data. They referred to the 2010 census, where the Census Bureau determined that when broken up by race the data showed undercounts among African-Americans and Hispanics and overcounts among whites -- so while the total number was accurately represented, the different racial communities involved were not.
During closing arguments on Tuesday, the administration also introduced another idea: that the current political environment may already keep noncitizens from responding to the census, regardless of whether the citizenship question is included.
Another key issue in the case is whether the challengers can question Commerce Secretary Wilbur Ross -- who has jurisdiction over the census -- about his rationale for making the decision.
During closing arguments on Tuesday, Judge Jesse Furman repeatedly asked Justice Department attorney Brett Shumate why Ross hadn't been deposed in the case. The questioning drew a reaction from some in the courtroom, who nodded in agreement. Shumate replied that it is not normal for someone in Ross' position to be deposed, and he noted that the Supreme Court had blocked Ross' deposition.
As the case drew to a close, both sides projected optimism about their arguments.
"Secretary Ross, the only person with legal authority over the census, reasonably decided to reinstate a citizenship question on the 2020 census in response to the Department of Justice's request for better citizenship data, to protect voters against racial discrimination," Justice Department spokesperson Kelly Laco said in a statement.
"The record clearly shows that the Secretary's decision to demand citizenship status on the 2020 Census is illegal," responded Amy Spitalnick, a spokeswoman for the New York attorney general. "We're confident in the strength of our case."
Although the Justice Department wants the issue resolved long before the deadline to print the questionnaire, it has also twice asked the Supreme Court to step in to delay the trial because of a dispute concerning discovery.
The justices rejected the first request on November 2 and have yet to respond to the unusual letter that Francisco penned on the eve of closing arguments suggesting that the justices should reconsider their decision, especially because they have decided to hear arguments on the discovery issue related to the trial.
Those arguments, which will occur on February 19, will target whether challengers should be able to introduce evidence outside of the official record, beyond what the government says it based its decision on when it decided to reinstate the question.
The challengers hope to get to the rationale behind the decision, which they say was made to reduce the representation of immigrant populations.
The administration argues that the decision was made in part to comply with the Voting Rights Act and challengers should not be allowed to go beyond the administrative record.
Furman has lambasted the department's repeated attempts to delay the trial, writing in one order that "enough is enough." He pointed out that any ruling from his court "will not hinder a higher court from granting full relief on appeal."
Furman said on Tuesday that he will issue his decision in the case within a couple of weeks.