A client state is a state that is economically, politically, or militarily subordinate to another more powerful state (termed controlling state in this article) in international relations. Types of client states include: satellite state, associated state, puppet state, puppet monarch, self-governing colony, neo-colony, protectorate, vassal state, and tributary state.
Ancient states such as Persia and Parthia, Greek city-states, and Ancient Rome sometimes created client states by making the leaders of that state subservient, having to provide tribute and soldiers. Classical Athens, for example, forced weaker states into the Delian League and in some cases imposed democratic government on them. Later, Philip II of Macedon similarly imposed the League of Corinth. One of the most prolific users of client states was Republican Rome which, instead of conquering and then absorbing into an empire, chose to make client states out of those it defeated (e.g. Demetrius of Pharos), a policy which was continued up until the 1st century BCE when it became the Roman Empire. Sometimes the client was not a former enemy but a pretender whom Rome helped, Herod the Great being a well-known example. The use of client states continued through the Middle Ages as the feudal system began to take hold.
In the 13th century, Goryeo dynasty of Korea was overrun by the Mongols who founded the powerful Mongol Empire. After the peace treaty in 1260 and the Sambyeolcho Rebellion in 1270, Goryeo became a semi-autonomous client state of the Yuan dynasty for about 80 years.
The Austro-Hungarian Empire tried to make Serbia a client state in order to form a Christian opposition to the Ottoman Empire. That changed after a revolution in Serbia in 1900. Serbia now came under Russian protection, which was forming a pan-Orthodox opposition to the Latin Christianity represented by the Austro-Hungarian empire. In 1914, Russia repeatedly warned the Austro-Hungarian Empire against attacking Serbia. When it did attack, Russia mobilized its army. Russia also wanted Bulgaria and Montenegro as client states.
Great Britain and Austria both considered Serbia as a client state controlled by Russia. Most historians call Serbia a client state but historian Christopher Clark disagrees. He says the Russians made a mistake in thinking Serbia was a client state. In an unpublished commentary Clark argues:
"It was a risk enhancing initiative [of Russian Foreign Minister Serge Sazanov]
to allow Serbia to become to see Serbia as a kind of client; ... Serbia, to my knowledge, has never been a client of anyone. [...] This is a mistake, when Great Powers think they can secure the services of "client states"; That Those "clients" are never in fact "clients"! That's a mistake that is presumably going to continue being made by our political leaderships, though one hopes one day it will stop."
During the Revolutionary and Napoleonic eras (1789–1815), France conquered most of western Europe and established several client states. At first, during the French revolutionary wars these states were erected as republics (the so-called "Républiques soeurs", or "sister republics"). They were established in Italy (Cisalpine Republic in Northern Italy, Parthenopean Republic in Southern Italy), Greece (Septinsular Republic), Switzerland (Helvetic Republic and Rhodanic Republic), Belgium and the Netherlands (Batavian Republic).
During the First French Empire, while Napoleon and the French army conquered Europe, such states changed, and several new states were formed. The Italian republics were transformed into the Kingdom of Italy under Napoleon's direct rule in the north, and the Kingdom of Naples in the south, first under Joseph Bonaparte's rule and later under Marshal Joachim Murat. A third state was created in the Italian Peninsula, the Kingdom of Etruria. The Batavian Republic was replaced by the Kingdom of Holland, ruled by Napoleon's third brother, Louis Bonaparte.
A total of 35 German states, all of them allies of France, seceded from the Holy Roman Empire to create the Confederation of the Rhine, a client state created to provide a buffer between France and its two largest enemies to the east, Prussia and Austria. Two of those states were Napoleonic creations: the huge Kingdom of Westphalia, which was controlled by Jerome Bonaparte, the Emperor's youngest brother; and the Grand Duchy of Würzburg.
In the 20th century, France started to apply the concept of Françafrique, its name for its former African colonies, sometimes extended to the former Belgian colonies. At present the term is used on some occasions to criticise the allegedly neocolonial relationship France has with its former colonies in Africa.
The countries involved provide oil and minerals important to the French economy. In addition, French companies have commercial interests in several countries of the continent.
In the British Empire the Indian Princely States were technically independent and were technically given their separate independence in 1947 (although the Nizam of Hyderabad indeed opted for independence but could not retain his independence from India). Egyptian Independence in 1922 technically ended a British protectorate in Egypt. Sudan continued to be governed as Anglo-Egyptian Sudan until Sudanese independence in 1956; Britain also had an interest in Egypt until the Suez Crisis was over. Iraq was made a kingdom in 1932. In each case the economic and military reality did not amount to full independence, but a status where the local rulers were British clients. Similarly in Africa (e.g. Northern Nigeria under Lord Lugard), and Malaya with the Federated Malay States and Unfederated Malay States; the policy of indirect rule.
After France was defeated in the Battle of France, Vichy France was established as a client state of Nazi Germany, which remained as such until 1942 when it was reduced to a puppet government until its liberation in 1944. Germany also established, in its newly conquered Eastern territories, client states including the Slovak Republic, the Croatian State and the Albanian Kingdom.
The term applied to authoritarian regimes with close ties to the United States during the Cold War, more appropriately referred to as U.S. proxy states, such as South Vietnam, Indonesia (1966–1998) under the Suharto Regime, Iran until 1979, Cambodia under the regime of Lon Nol from 1970 to 1975, the Philippines under Ferdinand Marcos from 1965 to 1986, and Saudi Arabia. U.S. - Iran relations under the Shah (reigned 1941 to 1979) have been cited[by whom?] as a modern political-science case-study.
The term might also arguably be used for those states extremely economically dependent on a more powerful nation. The three Pacific Ocean countries associated with the United States under the Compact of Free Association (the Federated States of Micronesia, the Marshall Islands and Palau) may fall somewhat[quantify] in this category.
In the late 19th century, the Japanese Empire gradually reduced Joseon Korea's status to that of a client state. In the early 20th century, this was converted to direct rule. Manchukuo, in contrast, remained a puppet state throughout World War II.
Soviet proxy or "client" states included much of the Warsaw Pact nations whose policies were heavily influenced by Soviet military power and economic aid. Other third world nations with Marxist-Leninist governments were routinely criticized as being Soviet proxies as well, among them Cuba following the Cuban Revolution, the Democratic People's Republic of Korea, the People's Republic of Angola, the People's Republic of Mozambique, the Democratic Republic of Afghanistan, and the Democratic Republic of Vietnam (North Vietnam). Within the Soviet Union itself, the Ukrainian SSR and the Byelorussian SSR, had seats at the United Nations, but were actually proper Soviet territory.
These countries have to varying degrees been called client states of Iran.
There are three Pacific Island states that are under the Compact of Free Association: