Which new commitment did the US undertake to fulfill policies such as those described in the excerpt?

The commitment to military intervention in foreign civil wars and nation-building reflects a broader trend in U.S. foreign policy during particular historical periods, especially in the late 20th and early 21st centuries. This approach involves not only direct military involvement but also a focus on establishing and supporting political and social structures in war-torn regions. By engaging in nation-building, the U.S. aimed to promote stability, democracy, and economic development, particularly in countries experiencing conflict or instability.

This commitment aligns with the context of various U.S. interventions, such as those in Iraq and Afghanistan, where the goal extended beyond merely defeating adversaries to include rebuilding the political and social fabric of these nations. Such actions signify a proactive, interventionist stance that sought to reshape global affairs according to American ideals and interests.

The other options do not encapsulate the depth or the scope of the U.S. commitment as described. Economic sanctions, while a legitimate form of policy, generally serve to coerce a change without physical intervention. Diplomatic negotiations play a crucial role in foreign relations but do not represent the same level of direct engagement as military intervention. Similarly, international peacekeeping forces, often limited to multilateral efforts, do not convey the same unilateral commitment to nation-building