During internal deliberations over adding a citizenship question to the 2020 head count, Census Bureau analysts told Commerce Secretary Wilbur L. Ross Jr. that the question was unnecessary because existing federal files — including those in Homeland Security — could provide the same information more accurately and cheaply.

The Census Bureau said in a statement that it had not gathered data on noncitizens in recent censuses, but added that the new agreement with Homeland Security was neither unusual nor cause for concern.

The agency said that it routinely supplemented its economic and population surveys with personal files from other federal agencies like the Social Security Administration and the Internal Revenue Service, and that is required to strip all identifiable personal information from data it gathers before sharing statistics with the public or the rest of the government. Failure to do so is a federal crime.

The administration’s attempt to add the citizenship question had another setback on Wednesday when a second federal judge barred the addition of the question, ruling that the administration ignored both federal law and the Constitution in its zeal to obtain information on noncitizens.

A final decision on whether the census can include the citizenship question now rests with the Supreme Court, which has set arguments on the issue for April.