Analyse the changing world order since 1945, including the rise of superpowers, the post-Cold-War unipolar moment, globalisation, terrorism and the emergence of new powers.

What this dot point is asking

You must explain how and why the structure of international power has changed since 1945. Strong answers trace the shift from bipolarity through unipolarity towards multipolarity and weigh the forces, military, economic, ideological and technological, that drove these changes.

The bipolar superpower era (1945-1991)

The Second World War destroyed the old order in which several European great powers shared global dominance. By 1945 two superpowers, the United States and the Soviet Union, stood far above the rest in military and economic strength. The result was a bipolar world: two rival blocs, NATO and the Warsaw Pact, organised around opposing ideologies of capitalist democracy and communism, with most other states drawn into one camp or the other (or seeking neutrality through the Non-Aligned Movement).

International order in this period rested on nuclear deterrence, the United Nations (where the superpowers held vetoes on the Security Council), and the economic institutions created at Bretton Woods (1944), the International Monetary Fund and World Bank, which underpinned a US-led capitalist economy. Decolonisation, meanwhile, multiplied the number of independent states and shifted the arena of superpower competition to the developing world.

The unipolar moment and globalisation (1991-2001)

The collapse of the Soviet Union in 1991 left the United States as the sole superpower, opening what commentators called a unipolar moment. Some, such as Francis Fukuyama, suggested liberal democracy and capitalism had triumphed as the final form of government. US-led coalitions acted with new confidence, as in the Gulf War (1991) to reverse Iraq's invasion of Kuwait.

The 1990s accelerated globalisation: the integration of national economies through trade, finance, migration and technology. The World Trade Organization was founded (1995), and the spread of the internet and mobile communications transformed economies and societies. Globalisation increased prosperity and connection but also provoked criticism over inequality, the power of multinational corporations and the erosion of national control. Regional bodies such as the European Union (formed by the Maastricht Treaty, 1993) reshaped sovereignty in Europe.

Terrorism, new conflicts and shifting power (2001 onwards)

The terrorist attacks on the United States on 11 September 2001 reshaped international politics. The US-led "War on Terror" produced the invasions of Afghanistan (2001) and Iraq (2003); the latter, launched without clear UN authorisation, proved costly and divisive and damaged American prestige. Non-state actors, terrorist networks and later groups controlling territory, became central concerns of international security alongside traditional states.

Meanwhile economic power shifted. The rapid rise of China, following the market reforms begun under Deng Xiaoping after 1978, turned it into the world's second-largest economy and a strategic rival to the United States. India, Brazil and a resurgent Russia also asserted themselves, suggesting a move towards a more multipolar order. The Global Financial Crisis (2008) shook confidence in the Western-led economic model.

Drivers, debates and the order today

Several forces have driven the changing world order. Military power and nuclear weapons defined the superpower era. Economic strength has become increasingly decisive, explaining both the Soviet collapse and the rise of China. Ideology has mattered, the Cold War clash of systems, the post-1991 spread of liberal democracy, and its more recent challenges. Technology, from nuclear weapons to the internet, has repeatedly reshaped power and the speed of global change.

Historians and analysts debate where the world is heading. Some argue US power remains dominant; others see relative American decline and the return of great-power competition between the USA, China and Russia. Globalisation itself faces a backlash from nationalism and protectionism. For SACE answers, the key is to identify the structural shifts since 1945 and explain the forces behind them, rather than predicting the future.

Analysts disagree sharply about the present and future shape of the order. Realists such as John Mearsheimer foresee renewed great-power competition and treat the rise of China as a structural challenge to American primacy that makes conflict likely. Liberal internationalists emphasise the durability of institutions, trade and alliances that constrain rivalry. Declinist writers point to over-extension, the costs of the wars in Afghanistan and Iraq, and the 2008 crisis as evidence of relative American decline, while others note the persistence of US military spending, the dollar's role and the network of alliances. A strong SACE answer treats these as competing interpretations of the same evidence and avoids confident prediction, instead explaining what each school weights most heavily.