The Supreme Court has effectively blocked the Trump administration from adding a citizenship question to the 2020 census, giving a partial victory to states and civil rights groups who said the question would jeopardize what is perhaps the most crucial information the U.S. government collects. The case, Department of Commerce v. New York, arose after a number of states, cities and advocacy groups sued the Trump administration and claimed the process the administration used to add the citizenship question ran afoul of federal law. Commerce Secretary Wilbur Ross, who oversees the census, was set on adding the question and ignored clear evidence that showed it was a bad idea. U.S. District Judge Jesse Furman agreed with the plaintiffs in January, ruling the Trump administration had violated the Administrative Procedure Act and thus could not add the question. Two other judges later also struck down the citizenship question. In its ruling, the Supreme Court said that the Department of Commerce did not provide an adequate explanation for its decision and sent the case back to a lower court for further review. The surprising ruling would still allow for a citizenship question in future years. But it may make it impossible for a citizenship question to get on the 2020 census. The Census Bureau has repeatedly said it needs a final answer from the courts on the citizenship question by June 30 so it can start printing the census forms. President Donald Trump tweeted Thursday afternoon that he’s asking government lawyers if they can delay the Census to accommodate a citizenship question.

Seems totally ridiculous that our government, and indeed Country, cannot ask a basic question of Citizenship in a very expensive, detailed and important Census, in this case for 2020. I have asked the lawyers if they can delay the Census, no matter how long, until the..... — Donald J. Trump (@realDonaldTrump) June 27, 2019

.....United States Supreme Court is given additional information from which it can make a final and decisive decision on this very critical matter. Can anyone really believe that as a great Country, we are not able the ask whether or not someone is a Citizen. Only in America! — Donald J. Trump (@realDonaldTrump) June 27, 2019

“Given the time, given the level of mendacity that we’ve seen to date, it’s very difficult for me to imagine that succeeding,” said Dale Ho, a lawyer at the American Civil Liberties Union who represented a group of plaintiffs challenging the citizenship question. “You can’t just come up with a new reason after saying for months, there was no other reason.” The Justice Department did not immediately address whether it would continue to push for a citizenship question on the census. “We are disappointed by the Supreme Court’s decision today. The Department of Justice will continue to defend this Administration’s lawful exercises of executive power,” Kelly Laco, a DOJ spokeswoman, said in a statement. Although the Supreme Court said it did not disagree with the merits of adding a citizenship question, it said the Trump administration had not adequately explained its reasoning for adding the question. The Trump administration could attempt to further explain its reasoning, but it is unlikely the administration would be able to offer such an explanation in just a few days to meet the Census Bureau’s deadline.

The surprising ruling would still allow for a citizenship question in future years. But it may make it impossible for a citizenship question to get on the 2020 census.

It is undisputed that adding the citizenship question would have made it more difficult for the Trump administration to fulfill its constitutional mandate to count every living person in the country. A Census Bureau analysis estimated that adding the question would likely cause an additional 2 million households, roughly 6.5 million people, not to respond to the survey on their own. An inaccurate decennial census would have huge consequences. Businesses rely on census data to make informed decisions about their products, and the federal government uses it to distribute about $880 billion in federal funds each year. States also use census data to redraw the boundaries for electoral districts once every 10 years. Because of the sensitivity of census data, the U.S. Census Bureau carefully tests and calibrates each question before adding it. But Ross decided to add the question in 2018 without testing it at all. The Trump administration argued that the benefits of adding a citizenship question outweighed the risk that fewer people would be counted. The Justice Department formally requested in 2017 that the administration add the question so that it could better enforce the Voting Rights Act. Even though the Census Bureau advised Ross there were other ways to get the data the Justice Department wanted, Ross ultimately decided to add the question. The Trump administration also says it can mitigate any drop in self-response by extensively following up with people.

The Trump administration argued that the benefits of adding a citizenship question outweighed the risk that fewer people would be counted. ... The plaintiffs in the case, along with many civil rights groups, say the Trump administration’s justification for adding a citizenship question is a lie.