On 12 June 2009, the United Nations Security Council unanimously adopted Resolution 1874 under Chapter VII of the United Nations (UN) Charter . The resolution responded to the Democratic People's Republic of Korea (DPRK)'s decision to challenge the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and previous resolution 1718 by testing a nuclear bomb on 25 May 2009. Resolution 1874 tightened sanctions on security and expanded the arms embargo already outlined in resolution 1718. This article will use empirical evidence to analyze neorealism, hegemonic instruments theory, and constructivism as explanations for the Security Council's actions in this case. Ultimately, the article will argue that the actions of the Security Council were best explained by neorealist predictions, but that underlying constructivist norms and rules were also influential in Resolution 1874. Neorealism For Resolution 1874, Neorealism predicted that the Security Council Security would act as an alliance to balance threat states, as great power collusion to control smaller states, and as a forum in which great powers fight. The Security Council acted as an alliance that balanced voting members against the threat of 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 North Korea. other states. Each state supported its vote by explaining that North Korea posed a threat to the international community. For example, Yukio Takasu, representing Japan, said that the DPRK's acts “constitute a grave threat to his country's national security and international peace and security.” Because below... in the center of the paper... rol and Non-Proliferation. February 22, 2008. Pentagon Spending Request for Fiscal Year 2009 – Global Military Spending. Available online at: http://armscontrolcenter.org/policy/securityspending/articles/fy09_dod_request_global/. Accessed 14 November 2011. Twomey Christopher P. 2011. Asia's complex strategic environment: nuclear multipolarity and other dangers. Asia Policy 11 (1): 51-78United Nations Security Council. 12 June 2009. Resolution 1874 (2009). Available online at: http://www.un.org/ga/search/view_doc.asp?symbol=S/RES/1874%20(2009). Accessed 14 November 2011. United Nations Security Council. 5 November 2010. Report of the Group 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.