The fraudulent installation of him certainly was.
SOURCE https://www.law.cornell.edu/constitution-conan/article-2/section-3/the-president-as-law-enforcer
Powers Derived From The “Take Care” Duty The Constitution does not say that the President shall execute the laws, but that “he shall take Care that the Laws be faithfully executed,” i.e., by others, who are commonly, but not always with strict accuracy, termed his subordinates. What powers are implied from this duty? In this connection, five categories of executive power should be distinguished: first, there is that executive power which the Constitution confers directly upon the President by the opening clause of article II and, in more specific terms, by succeeding clauses of the same article; secondly, there is the sum total of the powers which acts of Congress at any particular time confer upon the President; thirdly, there is the sum total of discretionary powers which acts of Congress at any particular time confer upon heads of departments and other executive (“administrative”) agencies of the National Government; fourthly, there is the power which stems from the duty to enforce the criminal statutes of the United States; finally, there are so-called “ministerial duties” which admit of no discretion as to the occasion or the manner of their discharge. Three principal questions arise: first, how does the President exercise the powers which the Constitution or the statutes confer upon him; second, in what relation does he stand by virtue of the Take Care Clause to the powers of other executive or administrative agencies; third, in what relation does he stand to the enforcement of the criminal laws of the United States?701
Whereas the British monarch is constitutionally under the necessity of acting always through agents if his acts are to receive legal recognition, the President is presumed to exercise certain of his constitutional powers personally. In the words of an opinion by Attorney General Cushing in 1855: “It may be presumed that he, the man discharging the presidential office, and he alone, grants reprieves and pardons for offenses against the United States. . . . So he, and he alone, is the supreme commander in chief of the Army and Navy of the United States, and of the militia of the several States when called into the actual service of the United States. That is a power constitutionally inherent in the person of the President. No act of Congress, no act even of the President himself, can, by constitutional possibility, authorize or create any military officer not subordinate to the President.”702 Moreover, the obligation to act personally may be sometimes enlarged by statute, as, for example, by the act organizing the President with other designated officials into “an Establishment by name of the Smithsonian Institute.” Here, says the Attorney General, “the President’s name of office is designatio personae.” He was also of opinion that expenditures from the “secret service” fund, in order to be valid, must be vouched for by the President personally.703 On like grounds the Supreme Court once held void a decree of a court martial, because, though it has been confirmed by the Secretary of War, it was not specifically stated to have received the sanction of the President as required by the 65th Article of War.704 This case has, however, been virtually overruled, and at any rate such cases are exceptional.705
The general rule, as stated by the Court, is that when any duty is cast by law upon the President, it may be exercised by him through the head of the appropriate department, whose acts, if performed within the law, thus become the President’s acts.706 Williams v. United States707 involved an act of Congress that prohibited the advance of public money in any case whatever to disbursing officers of the United States, except under special direction by the President.708
The Supreme Court held that the act did not require the personal performance by the President of this duty. Such a practice, said the Court, if it were possible, would absorb the duties of the various departments of the government in the personal acts of one chief executive officer, and be fraught with mischief to the public service. The President’s duty in general requires his superintendence of the administration; yet he cannot be required to become the administrative officer of every department and bureau, or to perform in person the numerous details incident to services which, nevertheless, he is, in a correct sense, by the Constitution and laws required and expected to perform.709 As a matter of administrative practice, in fact, most orders and instructions emanating from the heads of the departments, even though in pursuance of powers conferred by statute on the President, do not even refer to the President.710
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