The United Nations has faced many challenges and difficulties in their operational capabilities and decision-making implementation since its post-World War II origins, especially during the decades of east-west Cold War. The two largest challenges that the United Nations faced during the Cold War, and still face today, are found in the five permanent members of the United Nations Security Council and private sector influence in the form of international organizations on permanent Security Council members, as well as all general assembly members, which impacts United Nations efforts, actions and missions.
The key issue when looking at the United Nations Security Council is the fact that each of the five permanent members of the Security Council held, and still holds, veto power that can block or shut down the intentions of the other members of the Security Council, as well as block the General Assembly vote. Looking at history, we can easily understand that the five permanent members of the United Nations Security Council were the major powers within the victorious Allied forces in World War II. What could not have been seen at the time was how the divide between expanding global capitalism and communism would deepened, and eventually become quite a serious threat toward future international conflict (as was eventually realized by the Bay of Pigs and the Cuban Missile Crisis). With the permanent members of the United Nations Security Council consisting of the United States, Russia (Soviet Union during the Cold War), Britain, France and China, it is easy to see how the Cold War balance of power between capitalism and communism often played out in the Security Council and limited or prevented actions by the United Nations concerning important crisis situations. One can analyze the actual historical statistics and see that “the five permanent members cast 199 vetoes between 1946 and 1989 - well over four per year - preventing the Council from taking action on many important matters”  due to conflicting individual state or private sector interests. This inherent trait of the Westphalia state, which is a defining characteristic of international politics, is unable to be extinguished even in the format of an international democratic organization designed to establish world peace…as the concept itself is an oxymoron.
The paralysis of the United Nations due to the permanent members of the Security Council and their politics can be seen more in-depth by taking a closer look at their actions during the Cold War. The Soviets led all permanent Security Council members in veto usage and in the first ten years of the United Nations actually utilized veto power an incredible eighty times, often as payback for the United States refusal to admit Soviet Republics into the United Nations, while the United States has been a consistent protector of Israel through veto usage, which was considered a strategic Cold War ally in an excellent geographical location . The British and French veto was used, alongside of the United States, during the Suez Canal Crisis when Israel launched a military offensive (followed by France and Britain, to liberate the Egyptian nationalized canal, which was of major private sector interest for the capitalist west. The permanent member of the United Nations Security Council who cast the least amount of vetoes was China, who had cast one veto during the Cold War decades.
In addition to the structural flaws of the United Nations Security Council during the Cold War, and today, the United Nations also found its efforts challenged by capitalism and the private sector dollar, which influences states and international organizations in the pursuit of profit generation. The fact that the International Monetary Fund was “created in the midst of the war, at the United Nations Monetary and Financial Conference” hints that the United Nations would never be capable of being an unbiased international organization capable of placing true humanitarian efforts above individual state and private sector interests. The large sums of IMF and United States capital that was invested into post-war Europe through the Marshall Plan, which required protection in the form of the North Atlantic Treaty Organization, further laid the foundation for problems within the United Nations as the main permanent members vied for their individual interests with the U.S., Britain and France holding a stacked deck against Russia while China remained introverted on domestic issues and development.
In closing, the largest challenges facing the United Nations during the Cold War are the same challenges that hamper it today and fill its actions with hypocrisy. Those challenges are embedded in the charter of the United Nations, as the United Nations was no more than an attempt to consolidate international power within a five-seat council of an international organization. While during the Cold War, the United Nations was often divided between capitalist and communist interests, today we see the same fragmented politics at play in areas of the world such as the civil power struggle occurring in Syria and the nuclear talks with the state of Iran.
 Celine Nahory. 2004. “The Hidden Veto”. Global Policy Forum, May 2004. Accessed on April 25, 2015. https://www.globalpolicy.org/security-council/42656-the-hidden-veto.html
 Aleksandra Czajka. 2011. “The Analysis of the Veto Power in the United Nations Security Council”. Pompeu Fabra University: Barcelona. Accessed on April 25, 2015. http://www.academia.edu/4028521/The_analysis_of_the_Veto_Power_in_the_United_Nations_Security_Council_Public_International_Law
 International Monetary Fund. 2012. “The IMF and the Force of History: 10 Events and 10 Ideas That Shaped the Institution”. International Monetary Fund, p.5. Accessed on April 25, 2015. http://www.imf.org/external/pubs/ft/history/2012/pdf/prologue.pdf