9. As the main author of American foreign policy, the President acts as the nation's

chief executive

chief of party

chief diplomat

commander in chief

As the main author of American foreign policy, the President acts as the nation's chief diplomat.

Explanation:

The President of the United States, besides being the head of the Executive Branch and administering the country, has other important functions. Among them, it stands out that of being Head of State and representing the nation before other countries.

Within this function, the President is considered as the Chief Diplomat, since it is he who determines the foreign relations and diagrams the foreign policy of the nation, aided by the Secretary of State. It is the President who controls the guidelines of foreign policy, determines with which other nations sign treaties, have commercial relations or collaborate, and with which not.