On June 12, 2009, the United Nations Security Council unanimously adopted Resolution 1874 under Chapter VII of the United Nations Charter (UN). The resolution responded to the Democratic People's Republic of Korea's (DPRK) decision to challenge the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and the previous Resolution 1718 by testing a nuclear bomb on May 25, 2009. Resolution 1874 strengthened security sanctions. and expanded the arms embargo already outlined in Resolution 1718. This article will use empirical evidence to analyze neorealism, hegemonic tools theory, and constructivism as explanations for the Security Council's actions in this matter. Ultimately, the article will argue that the Security Council's actions were best explained by neorealist predictions, but that underlying constructivist norms and rules were also influential in Resolution 1874. NeorealismFor Resolution 1874, the Neorealism predicted that the Security Council would have acted as an alliance to balance states against a threat, a collusion of great powers to control lesser states, and a forum for great powers to fight each other. The Security Council acted as an alliance that balanced voting members against the threat from the DPRK when they unanimously supported Resolution 1874. The DPRK posed a threat not only because of its nuclear weapons, but also because it could potentially provide its nuclear knowledge and materials to other states. Each state supported its vote by explaining that the DPRK posed a threat to the international community. For example, Yukio Takasu, Japan's representative, said the DPRK's actions "pose a serious threat to his country's national security and international peace and security." Because, under ...... middle of paper ...... role and Non-Proliferation. February 22, 2008. Pentagon Spending Request for Fiscal Year 2009 – Global Military Spending. Available online at: http://armscontrolcenter.org/policy/securitysending/articles/fy09_dod_request_global/. Accessed November 14, 2011. Twomey Christopher P. 2011. Asia's Complex Strategic Environment: Nuclear Multipolarity and Other Dangers. Asia Policy 11 (1): 51-78 United Nations Security Council. June 12, 2009. Resolution 1874 (2009). Available online at: http://www.un.org/ga/search/view_doc.asp?symbol=S/RES/1874%20(2009). Accessed November 14, 2011. United Nations Security Council. 5 November 2010. Report of the Panel of Experts established pursuant to resolution 1874 (2009). Available online at: http://www.securitycouncilreport.org/atf/cf/%7B65BFCF9B-6D27-4E9C-8CD3-CF6E4FF96FF9%7D/DPRK%20S%202010%20571%20PoE%20Report.pdf. Accessed November 14 2011.