Two more memos, from 1980 and 2008, are yet more significant and on point. They hold that the DOJ “may not” prosecute criminal contempt charges against a current or former White House official who ignores a congressional subpoena based on an assertion of executive privilege. “As a matter of statutory interpretation and the constitutional separation of powers,” the reasoning goes, the statute was not intended to, and could not lawfully, apply to such contempt claims.

And indeed, since the 1980s, the DOJ has rejected a long list of criminal contempt referrals that turned on executive privilege. For example, Congress referred Obama administration Atty. Gen. Eric H. Holder Jr. for criminal contempt during the Fast and Furious investigation, but the department declined to go forward.

In those cases, of course, it was the sitting president who asserted executive privilege. President Biden has made it clear that he is not going to invoke the privilege as regards the Jan. 6 investigation, but here too Garland faces a complication.

In 1977, in the Supreme Court case Nixon vs. General Services Administration, the decision acknowledged that even former presidents could assert executive privilege.