WaPo:

The Justice Department said Wednesday that it will not comply with a congressional subpoena for a Trump administration official to testify in a House panel’s investigation of the addition of a citizenship question to the 2020 Census.

In a letter to the House Oversight and Reform Committee, Assistant Attorney General Stephen E. Boyd informed the panel that John Gore, the principal deputy assistant attorney general for the Justice Department’s civil rights division, will not give a deposition.

Gore’s refusal to appear before the committee is at the direction of Attorney General William P. Barr, according to the letter, escalating the already explosive fight between the executive and legislative branch.
Boyd said the reason Gore would not appear stemmed from the panel’s refusal to allow a department attorney to join him for the deposition.

Rep. Elijah E. Cummings (D-Md.), chairman of the committee, has threatened to hold Gore in contempt if he does not show.