The bipartisan leaders of the House Oversight and Government Reform Committee and its subcommittee overseeing the census are questioning why the Commerce Department is no longer pursuing the idea of using letter carriers as enumerators for the 2020 headcount.

In a letter to the department, they noted that Commerce and USPS have been working since 2016 on a partnership with the intent to conduct a pilot test this year. The Census Bureau had told the committee in a briefing in January that the reasoning was that the USPS “maintains an experienced labor force that not only has public trust, but also a detailed knowledge of addresses and residential patterns in the communities they serve,” in the letter’s words.

However, the department more recently told the committee that it no longer intends to conduct that pilot program in the upcoming test due to issues regarding data privacy, and “as a result, this concept is not likely to be utilized” during the census, their letter says.

They asked for explanations of the legal impediments that Commerce sees and what changes in law would be needed to allow the test to go forward–a suggestion of the committee’s willingness to pursue a change in law if needed.