Whether a former President has criminal immunity for conduct undertaken while serving as President.
Holding
Yes. A former President has absolute immunity for conduct within his exclusive constitutional authority, at least presumptive immunity for other official acts, and no immunity for unofficial acts.
Reasoning
The Court grounded immunity in the separation of powers and Article II's vesting of the executive power in a single President. The President's duties are unusually broad and sensitive, and criminal liability for official decisions could chill the energetic and independent exercise of executive power.
When the President acts within a sphere of constitutional authority that is both conclusive and preclusive—meaning Congress cannot regulate the subject and courts cannot review the President's discretion—Congress may not criminalize that conduct. The Court therefore held that immunity in this core sphere is absolute.
For official conduct outside the President's exclusive authority, the Court relied on Nixon v. Fitzgerald's concern that litigation may distort presidential decisionmaking, as well as the qualified protection for presidential communications recognized in United States v. Nixon. A criminal prosecution, with its risks of trial, conviction, and imprisonment, poses an especially serious intrusion on the Executive Branch.
The Court held that an official act is protected unless the Government can show that applying a criminal prohibition would pose no danger of intrusion on executive authority or functions. The Court left open whether this protection for noncore official conduct ultimately must be absolute rather than presumptive.
Unofficial conduct receives no immunity because the separation-of-powers rationale is functional, not personal. It exists to protect the Presidency's constitutional functions, not to place a President beyond ordinary law for private acts.