What is the name of the political theory that if one nation comes under Communist control, neighboring nations will also come under Communist control?

• A. Domino Theory
• B. Contagion Theory
• C. Bandwagon Theory
• D. Spiral of Influence

Answer: (A)

The tested idea is that political shifts in one country can trigger similar shifts in neighboring countries, creating a chain-reaction. This is known as the Domino Theory. It framed the Cold War as a regional contest: if a country in a region fell to communism, its neighbors would be likely to follow unless countered. It guided U.S. policy, helping justify aid, alliances, and sometimes intervention to prevent a slide to communist control in nearby nations. Other ideas describe different mechanisms—contagion through networks, or countries joining a trend for perceived advantage—but the specific name for this feared sequential spread is the Domino Theory.