Which role of the president is portrayed in this cartoon and why?

Diplomacy

The role that is demonstrated in this cartoon is that of diplomacy. Diplomacy refers to the practice of conducting negotiations between representatives of different states. Although the United States employs staff that focuses on diplomacy (such as ambassadors), the President also engages in diplomacy when addressing other leaders and conversing with them. In this case, the author implies that Trump is not a good diplomat due to his temper and ego.