This looks new to me. It becomes hard for prosecutors to prove anything when we can't ask about motives and the witnesses are 'privileged advisors'. From the officical court opinion -- note it is in paper-format with hyphens. (page 18: https://www.supremecourt.gov/opinions/23pdf/23-939_e2pg.pdf):
In dividing official from unofficial conduct, courts may
not inquire into the President’s motives. Such an inquiry
would risk exposing even the most obvious instances of of-
ficial conduct to judicial examination on the mere allegation
of improper purpose, thereby intruding on the Article II in-
terests that immunity seeks to protect. Indeed, “[i]t would
seriously cripple the proper and effective administration of
public affairs as entrusted to the executive branch of the
government” if “[i]n exercising the functions of his office,”
the President was “under an apprehension that the motives
that control his official conduct may, at any time, become
the subject of inquiry.”
(page 31)
The indictment’s
allegations that Trump attempted to pressure the Vice President to
take particular acts in connection with his role at the certification pro-
ceeding thus involve official conduct, and Trump is at least presump-
tively immune from prosecution for such conduct.