On July 1, 2011, the United Nations welcomed its newest member. South Sudan's January referendum on independence and subsequent peaceful separation from Sudan following years of violence marked a high point for U.N. peacekeeping, which had maintained the armistice there since 2005.

Yet, even as this tenuous victory unfolded, the Cȏte d'Ivoire's hellish descent into renewed violence reminded the world of U.N. peacekeeping's inconsistencies, shortcomings, and mounting challenges. Despite the presence of more than 9,000 U.N. peacekeepers, an estimated one million refugees were displaced by escalating violence in the wake of the country's contested November 2010 presidential elections. While U.N. and French forces eventually restored order in April, the peace remains fragile.

Also in Africa, the catastrophe unfolding in Somalia symbolizes some of peacekeeping's most abject failures. Twenty years, two U.N. peacekeeping missions, and one laborious African Union peacekeeping mission have done nothing to restore peace and stability to the Horn of Africa or to alleviate humanitarian crises there. Years of consternation over Somali pirates has shifted to impotent concern over a devastating famine exacerbated by decades of civil war.

What does the current state of affairs tell us about the nature of U.N. peacekeeping? Why, after more than six decades, is its legitimacy still debated regularly in the halls of the U.N. headquarters in New York City?

Undoubtedly, U.N. peacekeeping has restored peace and brought prosperity to millions of inhabitants in conflict zones around the globe.

Yet, expanding expectations for peacekeeping have strained the resources and mechanisms of the United Nations. Operational overstretch, shifting definitions of what peacekeeping should entail, and diminishing contributions (linked to a weakened global economy) are only the most recent obstacles to a function that has long tested the limits of the United Nations.

The Beginnings of United Nations Peacekeeping

In 1945, delegates from 50 nations met in San Francisco to draft a charter for a new international collective security organization determined "to save succeeding generations from the scourge of war." Since 1948, the United Nations (and its now 193 members) has conducted 67 peacekeeping operations from Central America to Southeast Asia.

For the vast majority of devastated populations around the world, the United Nations has become synonymous with peacekeeping. Yet, nowhere in the 111 articles that comprise the United Nations Charter can the word "peacekeeping" be found.

While not consciously chosen, "peacekeeping" operations arose from the UN's driving commitment to avoid the "scourge of war." The all-important justification for this peacekeeping function resides in Chapter VII of the charter, which stipulates that Security Council can authorize military action to safeguard international peace and security and respond to regional instability resulting from aggressive attacks on the sovereignty of member states.

Under Article 43 of this chapter, member states are obligated "to make available to the Security Council, on its call and in accordance with a special agreement or agreements, armed forces, assistance, and facilities … necessary for the purpose of maintaining international peace and security."

The United Nations, like many collective security alliances, was created in response to the last great threat to peace and security, in this case the two world wars. As such, the United Nations was built to respond to interstate conflicts (between two or more recognized states) and to safeguard the sovereignty of its member states. In order to avoid the inertness that plagued its predecessor, the League of Nations, the U.N. was endowed with rather robust enforcement protocols.