Over the past 100 years, the international system has been filled with a huge number of states that are unable to ensure their survival independently. This process was launched after the First World War, when the victorious powers were interested in creating a significant number of small countries that were absolutely dependent on them. In place of the destroyed Austro-Hungarian, German and Ottoman empires, a large group of state entities arose in Eastern Europe.
None of them could play even an insignificant role during the next big war, in 1939-1945. Even Poland, the largest in terms of population, was vanquished in a manner of weeks and later reborn thanks to the victorious Soviet army. The others may have been more or less successful in developing their own economic base during the 1918-1939 "truce", but their ability to ensure sovereignty with respect to national defence was immediately disproved. All these countries, except Finland, either fell under the pressure of internal circumstances, or were defeated because they acted as potential or active satellites of the opposing sides.
However, after the end of World War II, the "parade of sovereignties" continued on a global scale. Moreover, after 1945, the great powers acquired exceptional resources to manage international affairs - a colossal power gap that arose as a result of the creation of large arsenals of nuclear weapons. During the 1950-1970 period, the main engine of sovereignty was the desire of the two great powers - the USSR and the United States - to create a network of their own client states on the basis of the European colonial empires, unable to ensure their survival without the help of Washington or Moscow. In fact, the process which took place mirrored what had happened 25 years beforehand in Eastern Europe, only the other empires were divided - the British and French colonies.
Sometime later, albeit on a smaller scale, China also joined this movement. Before that point, Beijing’s funds had been limited enough that it could reliably promote a strategy of "national self-determination" to protect its own interests. China, in fact, found itself lagging behind in this race, and now it can only think about how client states of Russia or the United States can be so insecure about their future that they will transfer external governance into the hands of Beijing. So far, we have not seen convincing examples of such behaviour.
Moreover, after the collapse of their own colonial empires, Britain and France were able to regain control over the foreign policy of some of the entities that arose from their ruins. Now this control is carried out directly in very rare cases and mainly occurs through institutional mechanisms of interaction, with the European Union or other organisations of the community of market democracies.