Constitution of the United States of America
Article II: Executive Branch
Article 2, Section 2:  Presidential Powers

 The President shall be 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;

2.2.2   he may require the Opinion, in writing, of the principal
Officer in each of the executive Departments, upon any Subject
relating to the Duties of their respective Offices, and he shall
have Power to grant Reprieves and Pardons for Offences
against the United States, except in Cases of Impeachment.

2.2.3  He shall have Power, by and with the Advice and Consent
of the Senate, to make Treaties, provided two thirds of the
Senators present concur; and he shall nominate, and by and with
the Advice and Consent of the Senate, shall appoint
Ambassadors, other public Ministers and Consuls, Judges of the
supreme Court, and all other Officers of the United States, whose
Appointments are not herein otherwise provided for, and which
shall be established by Law:

2.2.4  but the Congress may by Law vest the Appointment of
such inferior Officers, as they think proper, in the President
alone, in the Courts of Law, or in the Heads of Departments.

2.2.5  The President shall have Power to fill up all Vacancies that
may happen during the Recess of the Senate, by granting
Commissions which shall expire at the End of their next Session.