Class 12 Political Science Chapter 1 Notes - The End of Bipolarity

Class 12 Political Science Chapter 1 explains one of the most important political transformations of the 20th century the collapse of the bipolar world order. After World War II, global politics was dominated by two superpowers: the United States and the Soviet Union. This division shaped international relations for more than four decades.

Bipolarity refers to a global power structure in which two dominant nations control world politics. After 1945:

• USA led the Capitalist Bloc
• USSR led the Socialist Bloc
• Both possessed nuclear weapons
• Both formed military alliances

The Cold War was an intense rivalry between the USA and USSR from 1947 to 1991. It was not a direct war but involved ideological conflict, nuclear competition and proxy wars.

The collapse of the Soviet Union in 1991 marked the end of bipolarity.

Major Reasons:

• Economic crisis and weak industrial growth
• Arms race pressure with USA
• Political reforms – Perestroika and Glasnost
• Rise of nationalist movements

In December 1991, the USSR split into 15 independent republics.

After the Soviet collapse, the United States became the only superpower. This period is called Unipolarity.

• US dominance in Gulf War (1991)
• Expansion of NATO
• Influence over IMF & World Bank
• Global spread of liberal democracy

Positive Outcomes:

• Reduced nuclear tension
• End of Cold War rivalry
• Increased globalization

Negative Outcomes:

• Political instability in former Soviet states
• Ethnic conflicts
• US military interventions

• Bipolarity
• Cold War
• Superpower
• Arms Race
• Perestroika
• Glasnost
• Unipolarity
• US Hegemony