The Evolution of International Relations

Why History Matters in International Relations

International Relations (IR) studies how states interact within an international state system and the historical, political and socio-economic consequences of that interaction. Because history and politics are deeply interlinked, the study of the past equips us with the background and context needed to make sense of the present. It is from the meeting point of these two disciplines that diplomacy was born.

A powerful reason to study history is that patterns repeat. The case of Afghanistan illustrates this: because of its strategic location, it has repeatedly been controlled through puppet or proxy rulers — the British installed Shah Shuja in the nineteenth century, and in the post–Cold War period the Americans backed proxy leaders such as Hamid Karzai and Ashraf Ghani. History not only repeats itself; it teaches recognisable patterns of repetition.

The Concept of International Society

Societies do not exist in isolation; they interact, and over time these interactions generate common rules, values and practices. When such shared rules bind a group of distinct political communities, they form an international society. According to the scholar Hedley Bull, a group of states forms an international society when, on the basis of common interests and values, they bind themselves by common rules and institutions — even while existing in a condition of international anarchy (the absence of a world government above the state).

The idea owes its origin to the European state system that crystallised after 1648, knit together by themes of sovereignty, legal equality and non‑interference. Though European in origin, the concept today applies to distinct political arrangements across the post–Cold War world.

International History of the Ancient Times

Long before the modern state, civilisations conducted themselves through well‑defined foreign policies. Elements of modern diplomacy — alliances, treaties, self‑interest, strategy, exchange of envoys, hegemony and shifting alignments — were already present.

The earliest recorded traces of diplomacy go back to around 3000 BC in Mesopotamia, and a peace treaty around 2300 BC between the ruler of Ebla and the Assyrians. Treaties governed border trade and grazing rights, were sealed with rituals, and their violation was believed to invite divine retribution — a reminder that ancient statecraft fused politics with religion.

Three classical cases reveal the intellectual roots of modern IR theory:

India — Realism in Kautilya’s Arthashastra

Self‑interest is the driving force of diplomacy and the state is the primary actor — an insight modern Realists would echo centuries later.
Alliances are always rooted in self‑interest (for territory, defence, or to crush a rival) and formalised by treaties signed in good faith.
Mandala Theory: a state’s immediate neighbour is a natural enemy, and the neighbour’s neighbour is a natural ally.
Diplomacy is a subtle act of aggression aimed at weakening the enemy; ambassadors are potential spies with diplomatic immunity. Foreign policy runs on expediency — the weaker king seeks peace, the stronger pursues conquest.

China — Liberalism and Competitive Diplomacy in Sun Tzu

Chinese diplomacy rested on a claim of cultural superiority, placing China at the apex of a cultural hierarchy.
Sun Tzu advocated great‑power relations built on cooperation and trust (a Liberal instinct), and famously prized ‘warfare by deception’ — to subdue the enemy without fighting.
His idea of competitive diplomacy held that a state without a strategy for diplomacy and war would fall captive to one that has such a strategy.

Greece — The Balance of Power

Greek city‑states (monarchies, aristocracies, oligarchies) were independent yet bound by common language and religion.
Sparta secured itself through an alliance network in the Peloponnese to prevent revolts by its subject class, the Helots.
Athens built the Delian League (~200 city‑states) to repel repeated Persian invasions.
After Athens’ defeat (404 BC), a coalition of Corinth, Thebes and Athens checked rising Spartan hegemony — an early demonstration of hegemonic assertion met by anti‑hegemonic coalition to preserve the balance of power.

Civilisation	Thinker / Text	Core Idea	Modern IR Parallel
Ancient India	Kautilya — Arthashastra	Self‑interest, Mandala theory, diplomacy as veiled aggression	Realism
Ancient China	Sun Tzu — The Art of War	Cooperation, trust, victory without battle	Liberalism
Ancient Greece	Sparta & Athens	Alliances to balance power and hegemony	Balance of Power

Common threads running from the ancient into later ages: alliance formation, the primacy of self‑interest, the value of cooperation, hegemonic assertion, and the centrality of treaties to diplomacy.

The Medieval Era: Feudalism, Papacy and the Two Romes

As ancient empires crumbled, weak successor kings gave way to land‑owning nobles (gentry/aristocracy) who controlled both land and armies — the essence of feudalism. Medieval society was closed and hierarchical: production served local needs, so long‑distance trade was minimal. Above the temporal order stood the Papacy, making the medieval West a complex mosaic of Church and monarchy.

The Splitting of Rome

Rome existed as a Republic (509–27 BC) before becoming an Empire (from 27 BC).
Administrative strain led Emperor Diocletian (c. 285 AD) to split it into Western Rome and Eastern Rome (the Byzantine Empire).
Western Rome, battered by Germanic invasions (Visigoths and others from c. 410 AD), slid into the Dark Ages for roughly 500 years; the Pope survived but could not project real authority.
Eastern Rome / Byzantium was resource‑rich and strategically placed as a transit hub for Euro‑Asian trade, and so consolidated and reformed.
Papal jealousy of the East led the Pope to crown Charlemagne (800 AD) as a western counterweight; rivalry culminated in the Great Schism of 1054, splitting the Churches of West and East.
Distracted by internal feuds, the East fell to the Seljuk Turks (defeat at Manzikert, 1071) and finally to the Ottomans, who captured Constantinople in 1453 — the symbolic close of the medieval age and the door to the modern world.

The Rise of Modern Europe and the Nation‑State

The transition from the medieval to the modern world was driven by a cluster of mutually reinforcing forces. The Crusades exposed Europeans to eastern luxuries, fuelling demand, trade, and the rise of a merchant and middle class in towns — slowly dissolving feudalism.

The Engines of Change

Fall of Constantinople (1453): scholars fled to Italy, where merchant‑ruled cities offered freedom of thought, reviving ancient Greek and Roman classics.
The Renaissance: a rebirth of reason, humanism and the critical spirit, freeing the mind from the tutelage of the past.
The Printing Press + rise of vernacular languages: spread classics and, crucially, the Bible, feeding a spirit of enquiry that seeded religious reform.
Gunpowder: kings no longer depended on nobles for armies, enabling royal consolidation and the decline of the feudal nobility.
Geographical Discoveries: the search for new trade routes (after Turks blocked old ones) produced a new merchant class and global ambition.
The Reformation (1517): Martin Luther’s challenge to the sale of indulgences by Pope Leo X split Christianity into Catholicism and Protestantism, triggering Europe’s wars of religion.

The Peace of Westphalia (1648) — Birth of the Modern State

The religious wars culminated in the Thirty Years’ War, closed by the Peace of Westphalia (1648) — the foundational moment of the modern international order. Its principles:

State sovereignty: rulers decide the religion and internal policy of their states.
Non‑interference in another state’s domestic affairs, and no Papal interference.
Co‑existing sovereign states whose aggression is checked by a balance of power; recognition of the independence of the Dutch Republic.
A precedent for peace by diplomatic congress and for national self‑determination — later called Westphalian sovereignty, central to international law ever since.

Renaissance + Reformation + Gunpowder + Discoveries → Decline of Feudalism & Papacy → Absolute Monarchy → Peace of Westphalia 1648 → Sovereign Nation‑State

Consolidation: From Westphalia to Utrecht

The War of the Spanish Succession (after 1700) ended with the Treaty of Utrecht (1713), which explicitly recognised the balance of power as the organising principle of European politics.
Interlocking state interests gave rise to permanent ambassadors and a professional diplomatic corps (staffed by rehabilitated nobles) — the birth of modern diplomacy under international law rather than religious sanction.

The period 1648–1713 thus institutionalised the pillars of modern international society: sovereignty, non‑intervention, permanent diplomacy, balance of power, and international law.

Enlightenment, Revolutions and Industrialisation

The Enlightenment deepened the culture of reason, producing two great consequences: political revolutions and the Industrial Revolution.
The American Revolution (1776) created a republic and inspired France; the French Revolution (1789) proclaimed liberty, equality, fraternity and unleashed national self‑determination across Europe.
The Industrial Revolution (aided by joint‑stock companies and the Glorious Revolution of 1688 stabilising Britain) demanded raw materials and markets, expressed economically as Mercantilism and politically as imperialism and colonialism in Asia and Africa.
Intense inter‑European rivalry over colonies, managed through shifting alliance systems, generated deep mistrust — setting Europe on the road to its first continental‑turned‑global conflict, the First World War.

Modern Times: The Road to the First World War

By 1900, industrialisation had produced several strong economies — Britain, France, Belgium, the Habsburg Empire, Italy, Japan, and two rising giants. The United States enjoyed nearly a century (c. 1800–1900) of largely uninterrupted growth, emerging as a strong player.

Germany, unified under Bismarck, industrialised rapidly, pursued colonies (Weltpolitik), and built naval power — igniting an intense Anglo‑German naval rivalry.

The Alliance System

Dual Alliance (1879) — Germany and Austria‑Hungary; expanded into the Triple Alliance (1882) with Italy.
Franco‑Russian Alliance (1894).
Entente Cordiale (1904) — Britain and France.
Anglo‑Russian Entente (1907) — completing the Triple Entente and encircling Germany.

Alliances alone did not cause the war; colonial rivalry and intense nationalism were bigger drivers. Serbian nationalism was central: Serbia sought a Greater Serbia (Yugoslavia) uniting Serbs and Croats and coveted Bosnia — which Austria (backed by Germany) was determined to suppress, while Russia backed Serbia.

The Pre‑War Crises (dress rehearsals for conflict)

Crisis	Year	Essence	Outcome
First Moroccan (Tangier)	1905–06	Germany tested the new Entente in Morocco	Algeciras Conference: France backed by Britain — Entente strengthened, Germany isolated
Bosnian Annexation	1908	Austria annexed Bosnia; Serbia enraged, Russia humiliated	Austria succeeds; Serbia turns anti‑Austria, Russia begins rearming
Agadir (Second Moroccan)	1911	Germany sent gunboat Panther to pressure France	Germany again backs down; Morocco a French protectorate
Balkan Wars	1912–13	Balkan League attacked a weakened Ottoman Empire	Treaty of Bucharest (1913); a resurgent, dissatisfied Serbia

The Spark and the War

28 June 1914: Archduke Franz Ferdinand assassinated at Sarajevo by Gavrilo Princip.
28 July 1914: Austria declared war on Serbia → Russian mobilisation → German declarations of war on Russia and France → German invasion of neutral Belgium brought Britain in.
The Zimmermann Telegram (Germany courting Mexico) and the 1917 Russian Revolution helped bring the USA in decisively on the Allied side (1917), ending the war.

A European conflict became the first modern, total and global war, born of alliances, mutual hostility and intense nationalism.

The Post–War Settlement and the League of Nations

Britain, France and the USA emerged victorious; Germany, Austria and Turkey lost. A cluster of treaties redrew the map — and, by sowing deep resentment, planted the seeds of the next war.

Treaty (Year)	Dealt with	Key Provisions
Versailles (1919)	Germany	War‑guilt & reparations; loss of colonies, ~13% of territory (incl. Alsace‑Lorraine to France) and ~10% of population; Polish Corridor; military caps; created the League of Nations
St. Germain (1919)	Austria	Break‑up of the Habsburg Empire; creation of Czechoslovakia and Yugoslavia
Neuilly (1919)	Bulgaria	Territory ceded to Greece, Romania and Yugoslavia
Trianon (1920)	Hungary	Hungary lost ~two‑thirds of its territory (Transylvania to Romania, etc.)
Sèvres (1920) → Lausanne (1923)	Turkey	Mandate system (Britain: Iraq, Palestine, Transjordan; France: Syria, Lebanon); Lausanne restored E. Thrace, Smyrna & Constantinople to Turkey

The League of Nations — Promise and Failure

Founded on collective security; achieved some successes — arbitrating the Aaland Islands dispute for Finland, and creating durable bodies (Labour, Refugee, Health organisations later inherited by the UN).
Fatally weakened when the US Senate refused to ratify it (rejecting Article X on collective resistance to aggression), leaving America outside.
Its failure to enforce compliance — exposed by Japan’s Manchuria invasion (1931) — signalled the collapse of collective security.

The Inter–War Years: Reparations, Depression and Dictatorship

Italy, unhappy with its post‑war gains and economically weakened, saw the rise of Mussolini and the first Fascist state. Germany faced the crushing weight of reparations, dividing victors: France wanted a weak Germany (occupying the Ruhr in 1923 when payments faltered), while Britain wanted Germany solvent enough to buy British goods.

Attempts to Stabilise — and their Collapse

Genoa Conference (1922), the Dawes Plan (1924) (US loans to enable reparations), Locarno Treaties (1925), and the Kellogg‑Briand Pact (1928) in which numerous nations renounced war.
Germany’s recovery under the Weimar Republic was steered by Gustav Stresemann (Nobel Peace Prize), who died in 1929.
The Great Depression (1929) shattered all of this. Mass unemployment and inflation discredited Weimar and opened the door to the National Socialist (Nazi) Party.
By 1933, Hitler came to power, defied Versailles, rearmed, preached racial superiority (leading to the Holocaust), and announced Lebensraum — ‘living space’ to be seized by conquest.

Two Pivotal Powers

Russia: From Tsarism to Communism

Defeat by Japan (1905) and the strains of WWI discredited the Tsar (Nicholas II).
February 1917 reforms proved inadequate; the October 1917 Revolution under Lenin (Bolsheviks) created the world’s first communist state, the USSR.
The Treaty of Brest‑Litovsk (1918) cost Russia vast western territory. After Lenin’s death (1924), Stalin consolidated power through the Purges and the Gulag, ruling until 1953.

Japan: The Power Actor of the Far East

Forced open by Commodore Perry (1853), Japan modernised through the Meiji Restoration (1868) and defeated China (1894–95) and Russia (1904–05).
It sided with the Entente in WWI and was a founder member of the League. The 1929 crisis empowered the army, which seized Manchuria (1931) against the government’s wishes; Japan then quit the League, exposing its impotence.

The Second World War (1939–1945)

Axis: Germany, Italy, Japan (with Hungary, Romania, Bulgaria).

Allies: USA, Britain, France, USSR and many others.

To realise Lebensraum, Hitler occupied the rest of Czechoslovakia and invaded Poland (September 1939), plunging the world into war.

Germany overran Denmark, Norway, Holland, Belgium and France at lightning speed, then fought the Battle of Britain (1940), where the RAF held firm.
Despite the Molotov–Ribbentrop (Nazi–Soviet) Non‑Aggression Pact of 1939, Hitler launched Operation Barbarossa against the USSR in June 1941, but stalled before Moscow and Leningrad in the brutal Russian winter.
7 December 1941: Japan attacked Pearl Harbor, bringing the USA into the war; Germany then declared war on the USA.
Allied landings in Sicily toppled Mussolini; Operation Overlord (D‑Day, 6 June 1944) opened the Second Front at Normandy.
Germany surrendered unconditionally (May 1945); the USA dropped atomic bombs on Hiroshima (6 Aug) and Nagasaki (9 Aug), forcing Japan’s surrender (August 1945).

Outcome: League of Nations replaced by the United Nations
• USA and USSR emerge as superpowers → the Cold War begins

The Cold War (1945–1991)

As the war ended, deep mutual suspicion between the USA (capitalist) and the USSR (communist) hardened into a global rivalry of containment, an arms race, and a nuclear standoff — fought everywhere except in a direct hot war between the two.

Institutionalising the Divide

Yalta and Potsdam (1945): established the United Nations; the stickiest issues were Poland and Germany.
Stalin built a belt of satellite states (Poland, Hungary, Bulgaria, Romania, Albania) — Churchill’s ‘Iron Curtain’ descended across Europe.
Truman Doctrine (1947): US support for peoples resisting communist subjugation (first applied to Greece and Turkey).
Marshall Plan (1947) (European Recovery Programme): US economic aid to rebuild Western Europe.
Berlin Blockade & Airlift (1948–49): Soviet blockade of West Berlin defeated by a Western airlift; led to the formation of NATO (1949) and two German states (Federal Republic / Democratic Republic).
Soviet counter‑structures: Cominform (1947), COMECON / Molotov Plan (1949), and the Warsaw Pact (1955).
The Berlin Wall (1961) became the enduring symbol of the Cold War until its fall in 1989.

Western Europe Integrates

European Coal and Steel Community (1951) → Treaty of Rome (1957) creating the European Economic Community.
Charles de Gaulle advanced Gaullism — a strong, independent France and Europe, keeping Anglo‑American dominance in check and ecognizing China (1964).

The Global Flashpoints

Flashpoint	Period	Core Story & Significance
Korea	1950–53	Divided at the 38^th Parallel; North (USSR/China‑backed) invaded South; UN/US intervention restored the line — hardened US resolve to contain communism
Indo‑China / Vietnam	1946–1973	After Dien Bien Phu (1954), Vietnam split at the 17^th Parallel; US mistook nationalism for communism; Vietcong guerrilla war forced US withdrawal (1973) and a united Vietnam
Cuban Missile Crisis	1962	After the failed Bay of Pigs, Soviet missiles in Cuba brought the world to the brink of nuclear war; resolved by a US no‑invasion pledge and quiet withdrawal of US missiles from Turkey

Détente, Renewed Tension and Collapse

Khrushchev pursued ‘peaceful coexistence’ and de‑Stalinisation, visiting the US (Camp David, 1959); but the U‑2 spy plane incident (1960) and Cuba/Vietnam revived tension.
The Cuban and Vietnam shocks pushed both sides toward disarmament: the Partial Test Ban Treaty (1963), later SALT I and SALT II.
Brezhnev maintained tight control via the Brezhnev Doctrine (justifying intervention to defend socialism, applied in the Prague Spring, 1968).
The Soviet invasion of Afghanistan (1979) ended détente and triggered a ‘Second Cold War’.
Gorbachev (from 1985) launched Glasnost (openness) and Perestroika (restructuring) to reform — not abolish — communism; instead, weakened central control let the satellites break free.
The Berlin Wall fell in 1989; power passed to Boris Yeltsin, and the USSR was dissolved in 1991, ending the Cold War.

The Fall of the Satellites (1989–91)

Poland: the Solidarity trade‑union movement under Lech Wałęsa won semi‑free elections; Tadeusz Mazowiecki became the first non‑communist PM (1989) and Wałęsa President (1990).
Hungary: after the crushed 1956 uprising (Imre Nagy), it transitioned peacefully by 1990 to multiparty democracy.
Germany: protesters pulled down the Berlin Wall (9 November 1989); Helmut Kohl led reunification (1990).
Czechoslovakia: after the suppressed Prague Spring (1968), the peaceful Velvet Revolution (1989) brought Václav Havel to power.

Systemic Shifts: Balance of Power → Collective Security → R2P

Across the modern period the governing logic of international order evolved through distinct phases:

Balance of Power (18th–19th century): after Napoleon, the Concert of Europe preserved peace among the great powers — while legitimising their domination of Asia and Africa.
Collective Security: the League of Nations (1919), the first near‑universal body, replaced the balance of power on the belief that the balance itself caused wars; the UN (1945) carried this forward more effectively.
Responsibility to Protect (R2P) — an emerging redefinition of sovereignty: a state must protect its own citizens, and if it fails and the UN Security Council so determines, the international community has a responsibility to intervene (invoked in Libya, 2011).

Balance of Power (Concert of Europe) → Collective Security (League → UN) → Responsibility to Protect

The World After the Cold War: From Unipolarity to Multipolarity

The collapse of the USSR left the USA as the sole superpower, ushering in a unipolar moment and a wave of globalisation. Yet the US, for the first post‑Cold‑War decade, remained ‘a superpower without a mission’ — possessing power without a clear purpose beyond promoting democracy and open markets.

Key Trends of the Present Order

9/11 and the Global War on Terror: US exceptionalism and its wars in Afghanistan (2001) and Iraq (2003) strained relations with much of the developing world.
Rise of China: accelerating economic power made China the principal challenger; the US responded with instruments like the Pivot to Asia. Beijing, in turn, dismisses Western groupings as products of a ‘Cold War mentality’ — evidence of a rivalry with Cold War echoes.
Drift toward multipolarity: rising powers — China, India and a resurgent Russia under Putin — are rebalancing the system away from unipolarity toward a volatile multipolar order.
Institutional reform pressure: frustration with US/Western dominance of the IMF and World Bank has driven emerging economies to build their own institutions — notably the BRICS’ New Development Bank and a growing push for alternative currencies and de‑dollarisation.
Russia–Ukraine War: rooted in the contest over Ukraine’s alignment, with Russia viewing NATO’s eastward expansion as an existential threat — the sharpest great‑power rupture since 1991, fragmenting global politics along new lines.
New transnational challenges: terrorism, poverty and inequality, the fallout of the Arab Spring and continuing West Asian instability, maritime piracy, and above all climate change — demanding a new, cooperative diplomacy rather than military solutions.

The Central Insight

Despite globalisation, the state endures as the core actor: globalisation itself can flourish only under the rule of law and stable social order that only states can guarantee. The twenty‑first‑century task is to manage an interdependent, multipolar world through cooperation and reformed multilateralism — the same instruments, refined, that history has handed down from Westphalia onward.

Recurring Themes for the Mains Answer

Continuity of concepts: self‑interest, alliances, balance of power and diplomacy run unbroken from Kautilya and the Greeks to the present multipolar order.
Sovereignty is not static: from absolute Westphalian sovereignty (1648) to conditional sovereignty / R2P — the meaning of the state’s supreme authority keeps evolving.
Punitive peace breeds war: the Treaty of Versailles shows how a vindictive settlement can plant the seeds of the next conflict.
Ideas drive order‑change: Renaissance, Reformation, Enlightenment and the twin Revolutions repeatedly reshaped the structure of world politics.
History rhymes: proxy politics in Afghanistan, US–China rivalry echoing the Cold War, and NATO expansion anxieties all show that patterns recur — the strongest reason to study IR through history.