Estonia was occupied on June 17, 1940, by Red Army troops and was forcibly incorporated into the Soviet Union on August 6, 1940. The United States never recognized the illegal annexation of the Baltic States, in conformity with the principles of the Stimson Doctrine (US Under Secretary of State Sumner Welles's Declaration of July 23, 1940), and more than 50 countries followed this position.
The Republic of Estonia, from 1940 through 1991, continued to exist as a state de jure according to international law during the whole period of its actual occupation and annexation. Therefore, some Estonian diplomatic and consular representations continued to function from 1940 through 1991 in some Western countries (the United States, Australia, the United Kingdom, and others), dealing with a limited part of state functions of the Republic of Estonia.
The heads of the Estonian Diplomatic Service were Johannes Kaiv (1940-1965) and Ernst Jaakson (1965-1991). In 1969, Ernst Jaakson signed the Apollo 11 Goodwill Messages on behalf of the Estonian nation, among leaders of 73 countries from around the world.