Would the question affect participation in the census?
The Census Bureau has acknowledged that inquiring about citizenship status could lower the response rate among immigrants and people of color. Census undercounts of minority groups have been a historic problem, attenuating their political influence and sparking distrust about the process, and critics say the citizenship question would make the problem worse.
By one government estimate, about 6.5 million people might not be counted if the citizenship question is allowed. Courts have found that Arizona, California, Florida, Illinois, New York and Texas might each lose seats in the House as a result.
When the case was argued in April, the Trump administration maintained that the benefits of obtaining more accurate citizenship data by asking the question would offset the potential harm from depressing the response rate among minority groups and noncitizens.
Do other countries ask about citizenship in their censuses?
Some do, including Canada, Australia, Ireland, Germany and Mexico, and the United Nations recommends the practice. The United States used to ask about citizenship as well, but since 1950 the question has not been included in the census forms that most people receive. (A much longer, more detailed questionnaire is sent to a small sample of households chosen at random.)
What did the Supreme Court say?
The justices sent the case back to a lower court. The majority opinion, written by Chief Justice John G. Roberts Jr., said the explanation offered by the Trump administration for adding the question was inadequate. But he left open the possibility that the administration could provide an adequate answer.
Federal judges in each of the three lawsuits opposing the addition of the citizenship question had ruled that Mr. Ross was not telling the truth about the rationale for adding the question. Information unearthed after those lower courts ruled has cast even more doubt on the government’s explanation.
What additional information might lower courts consider?
After Thomas B. Hofeller, a Republican strategist, died last summer, his estranged daughter found hard drives in her father’s house whose contents revealed that he had written a report in 2015 saying that adding a citizenship question to the census would give Republicans a significant advantage in drawing new legislative district lines.
Get more stuff like this
Subscribe to our mailing list and get interesting stuff and updates to your email inbox.