What concept did the League of Nations primarily promote?

The League of Nations primarily promoted the concept of collective security. This principle was founded on the idea that an act of aggression against one member nation would be viewed as an act against all member nations, thereby obligating them to come together to respond to the threat. The League aimed to maintain peace and prevent conflicts through collective action and diplomacy, which was a significant shift from the traditional practices of military alliances and unilateral actions that characterized international relations prior to its formation.

In promoting collective security, the League sought to create a framework that emphasized cooperation among nations to resolve conflicts peacefully, rather than allowing disputes to escalate into war. This was particularly important in the aftermath of World War I, as nations were eager to prevent a repeat of such devastation.

The other concepts listed do not encapsulate the League's primary objective. While the League did consider economic sanctions as a method to enforce its resolutions, its foundational mission centered on fostering a collective approach to security. Similarly, the idea of military expansion was contrary to the League's aims, which sought to limit arms and prevent aggression. Lastly, colonial governance was not a primary focus of the League; rather, the organization was more concerned with the self-determination of nations and the management of international disputes.