Federalist No. 69
Federalist No. 69, authored by Alexander Hamilton under the pen name Publius, is the sixty ninth of 85 essays. Titled "The Real Character of the Executive", Hamilton explains that the President is not to be involved with domestic affairs. He wrote:
The President is to be commander-in-chief of the army and navy of the United States. In this respect his authority would be nominally the same with that of the king of Great Britain, but in substance much inferior to it. It would amount to nothing more than the supreme command and direction of the military and naval forces, as first General and admiral of the Confederacy
Domestic affairs were to be solely under the purview of the Congress, and as commander in chief foreign affairs were the President's primary concern. A notable exception is the power of pardons.
It was published on March 14, 1788.