Confidentially incorrect as usual…

On the plus side. You e been learning a lot since I unblocked you, not sure how long it’ll last tho…

Section 4 addresses the case of a president who cannot discharge the powers and duties of the presidency but also cannot, or does not, execute the voluntary declaration contemplated by Section 3.[3]: 117  It allows the vice president, together with a “majority of either the principal officers of the executive departments or of such other body as Congress may by law provide”,[note 3] to issue a written declaration that the president is unable to discharge his duties. When such a declaration is sent to Congress, the vice president immediately becomes acting president,[note 4] while (as with Section 3) the president remains in office, temporarily divested of authority.[9]

John Feerick, the principal draftsman of the amendment,[3]: xii,xx [4]: 5 [10] writes that Congress deliberately left the terms unable and inability undefined “since cases of inability could take various forms not neatly fitting into [a rigid] definition … The debates surrounding the Twenty-fifth Amendment indicate that [those terms] are intended to cover all cases in which some condition or circumstance prevents the President from discharging his powers and duties”. [3]: 112  A survey of scholarship on the amendment found no specific threshold—medical or otherwise—for the “inability” contemplated in Section 4. The framers specifically rejected any definition of the term, prioritizing flexibility. Those implementing Section 4 should focus on whether—in an objective sense taking all of the circumstances into account—the President is “unable to discharge the powers and duties” of the office. The amendment does not require that any particular type or amount of evidence be submitted to determine that the President is unable to perform his duties. While the framers did imagine that medical evidence would be helpful to the determination of whether the President is unable, neither medical expertise nor diagnosis is required for a determination of inability … To be sure, foremost in [the minds of the framers] was a physical or mental impairment. But the text of Section 4 sets forth a flexible standard intentionally designed to apply to a wide variety of unforeseen emergencies.[4]: 7,20

Among potential examples of such unforeseen emergencies, legal scholars have listed kidnapping of the president and “political emergencies” such as impeachment. Traits such as unpopularity, incompetence, impeachable conduct, poor judgment, or laziness might not in themselves constitute inability, but should such traits “rise to a level where they prevented the President from carrying out his or her constitutional duties, they still might constitute an inability, even in the absence of a formal medical diagnosis.”