Constitution of the United States of America
Article II: Executive Branch
Article 2, Section 3:  Presidential Duties

 He shall from time to time give to the Congress Information
of the State of the Union, and recommend to their Consideration
such Measures as he shall judge necessary and expedient;

2.3.2  he may, on extraordinary Occasions, convene both
Houses, or either of them, and in Case of Disagreement between
them, with Respect to the Time of Adjournment, he may adjourn
them to such Time as he shall think proper;

2.3.3  he shall receive Ambassadors and other public Ministers;

2.3.4  he shall take Care that the Laws be faithfully executed,
and shall Commission all the Officers of the United States.