New evidence on the Trump administration’s meddling with the Census, confirming its focus on excluding noncitizens from the population count for reapportionment purposes.

The memo laid out a string of instances of political interference that senior census officials planned to raise with Wilbur Ross, who was then the secretary of the Commerce Department, which oversees the bureau. The issues involved crucial technical aspects of the count, including the privacy of census respondents, the use of estimates to fill in missing population data, pressure to take shortcuts to produce population totals quickly and political pressure on a crash program that was seeking to identify and count unauthorized immigrants.

Most of those issues directly affected the population estimates used for reapportionment. In particular, the administration was adamant that — for the first time ever — the bureau separately tally the number of undocumented immigrants in each state. Mr. Trump had ordered the tally in a July 2020 presidential memorandum, saying he wanted to subtract them from House reapportionment population estimates.