Answer: Chief Diplomat
Step-by-step explanation:
The President is the Chief Diplomat of a country which means that the president is the face of the United States to the world. The President is the one that negotiates with the rest of the world and speaks on behalf of the United States to the rest of the world.
In visiting Communist China, President Nixon acted upon his role as the Chief Diplomat and negotiated a new relationship with Communist China. A relationship which before his administration, had been hostile.