Diplomacy encompasses everything leaders do to advocate for their national interests around the world. It includes foreign aid, economic sanctions, back-channel conversations with hostile or neutral nations, negotiations to resolve disputes, and armed force when necessary. It also entails the training of ambassadors and other professional representatives who are sent to represent a country abroad.
The practice of diplomacy has a rich history that stretches back centuries. The rise and fall of empires, the emergence and spread of various religions and ideologies, and the exploration and colonization of the planet have all played an important role in shaping the international system as we know it today.
Great diplomats are good communicators. They understand how to present their options in a clear way, so their superiors can quickly and easily make decisions about what steps to take. They also are able to explain the results of meetings in a way that leaves their partners clearly understanding what options have closed or opened.
They are comfortable and disciplined in their tone, never overly sarcastic or professorial. They know what points they need to raise and when to do so, and they can convey those ideas in a manner that is both empathetic and persuasive.
They are patient, because they know that in many diplomatic situations it takes a long time to achieve their objectives. They understand that luck plays only a very minor role in the game of diplomacy, and they use cunning and cleverness, honesty and perfectly-timed betrayal to outwit their rivals.