The 1945 United Nations Charter , although containing stronger provisions for decision-making and collective military action than those of the League of Nations Covenant , does not represent a complete system of collective security , but rather a balance between collective action on the one hand and continued operation of the states system ( including the continued special roles of great powers ) on the other . States in UN collective security system are selective to support or oppose UN action in certain conflicts based on their self-interests . United Nations can be somehow seen as the platform for self-interest purposes for members in Security Council due to their Veto power and excessive assistance or aid . This has made those states to act unilaterally ignoring the approval , or flout orders of Security Council not to act unilaterally . The Iraq crisis is a clearer example as “ Rather than seek the global interest of peace and security through stability in Iraq and the Middle East region , the domination oriented members amassed their vast economic , diplomatic and military resources , captured and brazenly subjugated Iraq to an unprecedented condominial regime serving their economic interest under Iraq Reconstruction Programme . ” ( Eke , 2007 ) In addition , lack of geographical spread of members in Security Council causes unbalancing on the role of maintenance global peace and security . The voices of small countries can be only heard , but not all policies were adopted in response to them unless they serves the great powers ' interests . However , this does not mean collective security in the UN is completely fail . The role of the UN and collective security in general is evolving , given the rise of internal state conflicts . Since the end of World War II , there have been 111 military conflicts worldwide , but only 9 of these have involved two or more states going to war with one another . The remainder have either been internal civil wars or civil wars where other nations intervened in some manner . This means that collective security may have to evolve towards providing a means to ensure stability and a fair international resolution to those internal conflicts . Whether this will involve more powerful peacekeeping forces , or a larger role for the UN diplomatically , will likely be judged on a case-by-case basis . Collective defense is an arrangement , usually formalized by a treaty and an organization , among participant states that commit support in defense of a member state if it is attacked by another state outside the organization . NATO is the best known collective defense organization ; its famous Article 5 calls on ( but does not fully commit ) member states to assist another member under attack . This article was invoked after the September 11 attacks on the United States , after which other NATO members provided assistance to the U.S. War on Terror by participating in the War in Afghanistan
September 11 attacks
September 11 attacks
Collective security