The first significant diplomatic writer of the twentieth century is Ernest Satow. Satow owes his reputation in diplomatic theory to his book Guide to Diplomatic Practice, which was the first remarkable book in English language about the theory and practice of diplomacy when it was published in 1917. It is a comprehensive study which covers not only the roles and functioning of diplomatic institutions and actors but also gives a historical account of diplomacy.

Hugo Grotius, who is one of the contributors of the diplomatic theory, a great opponent of war and deems it acceptable when it is just, and for this reason according to him diplomacy has a vital role. His work Three Books On the Law of War and Peace is the reflection of this approach. He defines three methods to accommodate misunderstandings among states without a war. (Grotius, 1121-1127) The first of these methods is the conference method. The second method is arbitration between parties who do not belong to the same jurisdiction and have no common judge to appeal to, which he considers to be not only convenient but necessary that “Congresses of Christian states were held, where, by them who are no ways interested on one side or other, the differences of contending parties might be made up; and that some means were thought upon to oblige the parties at variance to accept of a peace upon fair and reasonable terms.” What Grotius has suggested is still an important method of conflict resolution in international relations and considered as one of the main functions of diplomacy. The third and the last method to prevent war according to Grotius is to cast lots.

Diplomacy, according to Machiavelli, must be permanent, in the sense that states should have diplomatic representatives, at least in those countries that they have high interests whether they are allies or enemies. Still even though he himself was a diplomat, Machiavelli believed that military power was more important than diplomacy. But because not all states had enough military power to pursue their aims, they needed diplomacy. Diplomacy according to Machiavelli is based on deception. This assumption of diplomacy is closely related to Machiavelli’s conception of human nature which he defines as “For it can be said about men in general that they are ungrateful, fickle, dissembling, hypocritical, cowardly, and greedy.”

French statesmen Richelieu has also formulated ideas on diplomacy. His theory of diplomacy can be derived from his Political Testament, in which he has penned political advice for Louis XIII. Having become the French prime minister in an age of continuous wars, Richelieu’s main concern was to establish peace and carry out peaceful relations with other states. For this reason he attributed great significance to diplomacy. The main theme of Richelieu’s theory is negotiations.

The main theme in Guicciardini’s theory, which is generally outlined in his History of Italy, is the value of good ambassadors, which he sees as a source of prestige for the price. According to him a well-trained, qualified ambassador is a sign of value of the prince as well and should be rewarded.

The correct answer is Choice D.