Union
Overview
Union (聯合, alliance/union) refers to an organization or system in which two or more individuals, groups, states, or political entities voluntarily or strategically combine to achieve a single purpose or interest. In international politics, it is sometimes distinguished from an alliance: whereas an alliance mainly refers to security and military cooperation, union is used as a superordinate concept that also includes political, economic, and cultural integration. A union is distinguished from a federation in that it creates a joint decision-making and enforcement structure without fully transferring the sovereignty of its members.
Main Content
Concepts and Types
Unions are divided into several branches according to the strength and purpose of combination. First, military-security unions are collective defense systems to respond to external threats, with the North Atlantic Treaty Organization (NATO) and the Warsaw Pact as representative examples. Second, political unions are forms in which multiple political forces or states share a single decision-making system, and the European Union (EU) is the most advanced case. Third, economic unions aim for phased integration such as customs unions, common markets, and monetary unions, corresponding to the ASEAN Economic Community and Mercosur. Fourth, electoral and party unions are temporary combinations formed to secure seats and change governments in a particular election or parliamentary composition.
Historical Background
The origins of unions go back to the Delian League and the Peloponnesian League of ancient Greek city-states. In modern times, after the Peace of Westphalia, as the logic of balance of power among sovereign states took hold, alliances and unions became key instruments of diplomacy. The Holy Alliance of the Congress of Vienna in 1815, the League of Nations after World War I, and the United Nations (UN) after World War II are examples of the concept of union expanding to the level of world order. In particular, the failure of the League of Nations and the founding of the UN show the process by which unions evolved beyond simple military alliances into an institutional framework for peacekeeping and cooperation.
Operating Principles and Limitations
For a union to be maintained, a shared perception of threat, complementarity of interests, and institutional devices to guarantee trust are necessary. The dilemma of collective action, the free-rider problem, and asymmetries of power among members are representative vulnerabilities of unions. In addition, a union led by a great power can constrain the autonomy of small states, and if internal disagreements grow, cohesion rapidly weakens. Historically, alliances have tended to disband once the threat disappears, suggesting that the durability of a union depends on how institutionalized it is.
Representative Cases
The European Union is the most deepened union, with a single market, a common currency, and supranational parliamentary and judicial systems. NATO is the archetype of a military union that mutually guarantees member security through a collective defense clause. ASEAN is a loose union model that prioritizes respect for sovereignty and the principle of non-interference in internal affairs, and is evaluated as an Asian-style mode of cooperation. BRICS began as a consultative body of emerging economies and, through repeated expansion, has taken on the character of an alternative union to the Western-centered order.
Latest Trends
In the international situation of 2024–2025, the landscape of unions is rapidly being reorganized. After Finland and Sweden joined, NATO has strengthened its defense posture in Northern Europe and the Baltic Sea and raised its defense burden-sharing targets. The European Union is attempting to transform into a geopolitical actor by discussing support for Ukraine, energy security, and joint defense procurement. After its 2024 expansion, BRICS is seeking to rally the Global South by increasing new member and partner countries, and in major countries, a dual trend is emerging in which national priority and bloc formation proceed simultaneously.
In South Korea, following the 2024 martial law crisis and impeachment political situation, coalitions between the ruling and opposition parties and alignments among parties entered a new phase, and in the 2025 early presidential election and state administration process, the effectiveness and limitations of coalition politics were highlighted again. Meanwhile, it is also a notable change that technology alliances and small-scale unions in the form of minilateralism are increasing in AI, semiconductors, and supply chains. This shows that unions are being reorganized around functional interests beyond ideology or region.
Related Topics
- [[Alliance]]
- [[European Union]]
- [[United Nations]]
- [[NATO]]
- [[Federalism]]
- [[International Politics]]
- [[BRICS]]