On these facts, I believe he does have immunity. Or at least a colorable argument that he does.
Excerpts from his brief below (The Lexis link requires a subscription.)
The structure of our government, the text of the Constitution and its early
commentators, common-law immunity doctrines, our political history, the Supreme
Court’s analogous immunity doctrines, and the policy considerations rooted in the
separation of powers all dictate that no President, current or former, may be
criminally prosecuted for his official acts unless he is first impeached and convicted
by the Senate. Nor may a President face criminal prosecution based on conduct for
which he was acquitted by the U.S. Senate. The indictment against President Trump
is unlawful and unconstitutional. It must be dismissed.
* * * *
SUMMARY OF ARGUMENT
I. President Trump has absolute immunity from prosecution for his official acts
as President. The indictment alleges only official acts, so it must be dismissed.
A. Seven considerations mandate the recognition of presidential immunity
from prosecution for official acts. First, criminal immunity has deep roots in the
separation of powers. Under Article II, § 1, the President is vested with the
Executive Power. The Judicial Branch may not sit in judgment, criminal or
otherwise, over his exercise of that power. As Chief Justice Marshall wrote in
Marbury v. Madison, the President’s official acts “can never be examinable by the
courts.” 5 U.S. (1 Cranch) 137, 165-66 (1803).
Second, the text of the Constitution, through the Impeachment Judgment
Clause, presupposes criminal immunity. That Clause dictates that a President may
be criminally charged only if he is the “Party convicted” in an impeachment trial.
U.S. CONST. art. I, § 3, cl. 7. Alexander Hamilton reinforced this understanding by
writing in The Federalist that the President may face criminal prosecution only
“afterwards” or “subsequent” to impeachment and Senate conviction. President
Trump was acquitted, not convicted, by the Senate after an impeachment, so he
retains immunity for his official acts.
Third, early commentators on the Constitution—including Chief Justice
Marshall, George Washington’s Attorney General Charles Lee, Alexander Hamilton,
Justice Joseph Story, and others—confirm that a President’s official acts are not
examinable by the Judicial Branch.
Fourth, at common law, immunity from criminal prosecution was far more
central to the concept of immunity than immunity from civil liability. The prospect
of senior officials facing “criminal charges” before a “possibly hostile judiciary” was
the “chief fear” that official immunity was designed to prevent. United States v.
Johnson, 383 U.S. 169, 180-82 (1966).
Fifth, the 234-year tradition of not prosecuting Presidents for official acts—
despite ample motive and opportunity to do so—provides powerful evidence that the
power to do so does not exist. “Perhaps the most telling indication of a severe
constitutional problem” with this “wholly unprecedented” prosecution “is a lack of
historical precedent to support it.” Seila Law, LLC v. CFPB, 140 S. Ct. 2183, 2201
(2020) (cleaned up).
Sixth, analogous immunity doctrines for legislators and judges, which are also
rooted in the separation of powers, support criminal immunity for a President’s
official acts. Legislative immunity “prevent[s]” legislative acts “from being made
the basis of a criminal charge against a member of Congress.” Johnson, 383 U.S. at
180. Excluding cases of bribery, which were long prosecutable at common law,
judicial immunity shields a judge from “indictment for any act done … by him,
sitting as judge.” Spalding v. Vilas, 161 U.S. 483, 494 (1896). Presidents’ official
acts are equally, if not more so, immune.
Seventh, policy considerations rooted in the separation of powers support
immunity. The President handles “especially sensitive duties,” Fitzgerald, 457 U.S.
at 746. The Presidency requires “bold and unhesitating action.” Id. at 745. The
threat of future prosecution risks “crippl[ing] the proper and effective administration
of public affairs.” Id. at 745 (quoting Spalding, 161 U.S. at 498). The President is
most likely to be “harassed by vexatious actions.” Spalding, 161 U.S. at 495. The
threat of indictment, conviction, and imprisonment by a politically motivated
successor—or by hundreds of local prosecutors, many in enclaves of political
hostility to the President—before a possibly hostile judiciary poses a far greater
deterrent to bold, fearless Executive leadership than civil liability.
Link: https://advance.lexis.com/f/courtlinkdocument/jobstatus/downloadfile/5554cba8-a52e-4545-ae36-1790d86d1a6c/urn:contentItem:69Y3-T5Y3-RRRR-W0HX-00000-00/0/0/d753532443e4243/0/blob/US_APP_CADC_23_3228_d753532443e4243_APPELLANT_BRIEF_2033200_filed_by_Donald_J