where after Biden was sworn in, there were cases that came up (like Mark Meadows) claiming "Executive Privilege), where that had been waived away by Biden.
This article has a whirlwind of info of that period and all the claims of "Executive Privilege" -
Meadows, other top Trump aides ordered to testify in Jan. 6 probe as judge rejects claims of executive privilege
ByJohn Santucci, Katherine Faulders, and Jonathan Karl
March 24, 2023, 1:36 PM
A federal judge has rejected former President Donald Trump's claims of executive privilege and has ordered Mark Meadows and other former top aides to testify before a federal grand jury investigating Trump's efforts to overturn the election leading up to the Jan. 6 attack on the U.S. Capitol, multiple sources familiar with the matter tell ABC News.
Meadows, Trump's former chief of staff, was subpoenaed along with the other former aides by Special counsel Jack Smith for testimony and documents related to the probe. Trump's legal team had challenged the subpoenas by asserting executive privilege, which is the right of a president to keep confidential the communications he has with advisers.
In a sealed order last week, Judge Beryl Howell rejected Trump's claim of executive privilege for Meadows and a number of others, including Trump's former Director of National Intelligence John Ratcliffe, his former national security adviser Robert O'Brien, former top aide Stephen Miller, and former deputy chief of staff and social media director Dan Scavino, according to sources familiar with the matter.
(snip)
Previously, Judge Howell had rejected Trump's claim of executive privilege to block the testimony of two top aides to Vice President Pence, Greg Jacob and Marc Short. In rejecting Trump's motion to block the testimony of Jacob and Short, the judge ruled that it is up to the current president to assert executive privilege, not a former president, according to sources familiar with the proceedings.
(snip)
45 (who was out of office at the time)
appealed and
the appellate court said, um nope. It never really went any further
and Meadows ended up testifying.
I believe the caveat may be only a "sitting President" can invoke "Executive Privilege". So a sitting one (at the time, Biden) could invoke it on behalf of a previous President (45 at the time), but in this case, that did NOT happen!