The United Nations is only as powerful as its Member states. It can call on its Members for support: financially, logistically or in troops and hope that they answer the call. If this call goes unanswered (as is currently the situation), what powers does the UN have to ensure enforcement or support?
The structures of the International Court of Justice, the UN’s principle judicial organ, are only meant to settle legal disputes between states, and rely on local enforcement structures to arrest and detain crime suspects. The International Criminal Court, which tries crimes against humanity and war crimes, is also reliant on local enforcement structures, which prevents it from trying many international criminals because of a lack of cooperation or capabilities of local enforcement.
Five permanent members of the UN Security Council (UNSC) enjoy a veto privilege, which means they can stop any action of the UNSC by exercising their veto. The UNSC is responsible for maintaining international peace and security, investigating disputes, recommending methods to solve disputes, regulating armaments, determining the existence of threats to peace or acts of aggression, recommending what actions are to be taken, applying economic sanctions and other measures to prevent or stop aggression, taking action against an aggressor, recommending admission of new Members to the UN, overseeing trusteeship functions of the UN, and recommending the appointment of the Secretary-General to the UN and Judges of International Court of Justice. Since the UN’s inception in 1946, there have been 261 vetoes in the Security Council: 124 by the USSR/Russia, 82 by the US, 32 by Britain, 18 by France and 6 by China. These vetoes have included subjects such as condemning the violence by the government of Zimbabwe against civilians following the elections in 2008 (vetoed by China and Russia), stopping Israeli military operations in Gaza in 2004 and 2006 (vetoed by the US), on taking action against the killing by Israeli forces of several UN employees and the destruction of the World Food Programme warehouse in 2002 (vetoed by the US), on establishing a UN observer force to protect Palestinian civilians in 2001 (vetoed by the US). Many others operations are never even brought to the table, since the veto will ensure the action cannot happen.
It is structures like these that allow major criminals to evade justice and limits the power of the UN. Combine this with incredible budget arrears owed to the UN by its Member states. The debt owed by the 15 largest payers of the peacekeeping budget is certainly a cause for concern, especially considering that peacekeeping support is so desperately needed in many areas of the world. The US currently owes $1.466 billion in debt to the UN; Japan owes $832 million; France owes $235 million; China owes $213 million; and Germany, the UK, Italy, Canada, Spain, Mexico, Korea, the Netherlands, Australia, Switzerland, and Russia are all among the top debtors. The hypocrisy that these countries all sponsor intense humanitarian aid (and state loans) to conflict zones, yet cannot manage to pay their promised share of peacekeeping debt should not go unnoticed. Requests for troop support to areas are also frequently ignored by the international community.
If countries ignore the UN and its missions, it loses its power and its meaning in the international community. The UN is important because it is the only place where all countries can work together and have a voice, and is the best chance for peace in the world. That being said, it is time the UN lived up to its original purpose, and created some means of enforcing its own legalities. The UN is capable of much more than it is currently doing, but it does not have the resources to do these things alone. It must have the support of its Members in the international community to work, who must practice what they preach and provide their promised share in the international community. The UN can work if it is provided the proper resources and support to actually run. Major violators should not be allowed to decide what methods of peace should be used in an area that they have a hand in violating. This is wrong and is preventing justice from existing in the world. All violators should be brought to justice, regardless of whether they hold a veto power or not.
 A full list of vetoes can be found at http://www.globalpolicy.org/security/membship/veto/vetosubj.htm