On January 20, 2017, Donald Trump will take the oath of office and become the 45th president of the United States. That oath states:
I do solemnly swear (or affirm) that I will faithfully execute the office of President of the United States, and will to the best of my ability, preserve, protect, and defend the Constitution of the United States.
The moment Trump takes that oath, he will violate it. This is because Donald Trump has refused to divest himself of his business, both domestic and foreign and will receive, as a result, on January 20, 2017, emoluments from foreign sources and domestic governments, federal, state and local.
Article 2 of the Constitution provides, in pertinent part:
The President shall, at stated Times, receive for his Services, a Compensation, which shall neither be increased nor diminished during the Period for which he shall have been elected, and he shall not receive within that Period any other Emolument from the United States, or any of them.
This provision states, in unmistakable terms that the president of the United States can receive only his salary as an “emolument” and is expressly barred from receiving any other compensation from the federal government and the States (which necessarily comprises local governments as well as they are creatures of State creation).