Justice Elena Kagan’s father was 3 years old when the census taker came to the family’s apartment on Ocean Parkway in Brooklyn, New York, on April 10, 1930.

Robert Kagan was initially wrongly listed as an “alien,” though he was a native-born New Yorker. The entry about his citizenship status appears to have been crossed out on the census form.

Vast changes in America and technology have dramatically altered the way the census is conducted. But the accuracy of the once-a-decade population count is at the heart of the Supreme Court case over the Trump administration’s effort to add a citizenship question to the 2020 census.

The justices are hearing arguments in the case on Tuesday, with a decision due by late June that will allow for printing forms in time for the count in April 2020.

The fight over the census question is the latest over immigration-related issues between Democratic-led states and advocates for immigrants, on one side, and the administration, on the other. The Supreme Court last year upheld President Donald Trump’s ban on visitors to the U.S. from several mostly Muslim countries. The court also has temporarily blocked administration plans to make it harder for people to claim asylum and is considering an administration appeal that would allow Trump to end protections for immigrants who were brought to this country as children.

The citizenship question has not been asked on the census form sent to every American household since 1950, and the administration’s desire to add it is now rife with political implications and partisan division.