Acting as a protecting power is part of Switzerland's tradition of providing good offices. A state that acts as a protecting power represents the interests of a country that has broken off diplomatic relations with another.
On 4 January 1961 the United States informed the Cuban government that it had broken off diplomatic relations. One day later, the Swiss ambassador in Washington at the time, August R. Lindt, received an official request from the United States for Switzerland to represent the interests of the United States in Cuba. The next day, the Swiss ambassador in Havana, Walter Bossi, was instructed to assume the protecting power mandate to represent the interests of the United States in Cuba. Cuba, for its part, asked (former) Czechoslovakia to assume responsibility for its diplomatic and consular interests regarding the United States. Because Czechoslovakia had no experience as a protecting power, the Swiss ambassador briefed his Czechoslovak colleague.
During its dual mandate as a protecting power for the United States and Cuba (the latter from 1991), Switzerland was able to exert its diplomatic influence on several occasions. In a letter sent at the beginning of January 2015, US Secretary of State John Kerry expressed his “deep gratitude“ for Switzerland’s efforts and its assistance as a protecting power for the United States in Cuba. The dedication of the people of Switzerland to bring about a rapprochement between the two countries is “an inspiration to us all and an example of patient action in the service of peace“.