Halford Mackinder, one of the founding fathers of geopolitics, once wrote "Who rules East Europe commands the Heartland; who rules the Heartland commands the World-Island; who rules the World-Island controls the world." Ukraine was one of the integral parts of the Heartland that he stated. Now, the crisis in Ukraine is becoming an arena for a major geopolitical confrontation.The problem in Ukraine that has been overshadowed in recent days with the mysterious loss of the Malaysian Airlines plane is quickly being transformed into a global problem instead of a regional challenge for countries in Eastern Europe. The crisis not only brought Western powers and Russia face to face in Crimea but is becoming a global chessboard in which global powers have stakes. The most significant centers of gravity in international relations, namely the United States and China and their positions and diplomatic steps regarding the crisis will be very important for the future of the conflict in Crimea, their bilateral relations, as well as the international system. The crisis and its outcomes will be a major determinant of future global geopolitics.The crisis in Ukraine is yet another serious test of U.S. leadership in terms of its international alliances, guarantees and assurances.The world is watching the reaction of the U.S. after Russia's invasion of Crimea.The crisis will have a major impact on its role in the new global system. However, the United States' status as the superpower (though a reluctant one) or the 1994 Budapest Memorandum in which the United Kingdom and U.S. gave some "assurances" to Ukraine about its political independence and territorial integrity (though it is not clear what these assurances are) in return for Ukraine to give up its nuclear arsenal is not the only reason the U.S. is part of this crisis.There is another very important dimension of the crisis, which relates to the future nonproliferation endeavors of the U.S., which is one of the significant pillars of Obama's foreign policy and one of the backbones of its policy in the Middle East.The military intervention of Russia in Crimea can seriously damage the prospect of a U.S.-Iranian deal. Since negotiations began, it was mentioned multiple times that the talks between Iran and P5+1 will have a clause related to the security of Iran in the case of elimination or serious limitation of its nuclear program. The Budapest Memorandum was issued as a possible framework in negotiations with Iran. Under these circumstances, if Iran sees that the memorandum will not bring any form of security to Crimea, it can drag its feet about a final agreement, which would seriously hamper U.S. foreign policy. Because of that, the U.S. would be looking for a formula that would entail policy moves that could show its commitment to states that gave up their nuclear weapons.The U.S. is not the only one looking for an appropriate policy response. China is also watching the situation closely and trying to modify its foreign policy in accordance with the changing circumstances. This position will have a dramatic impact on the future of global geopolitics. Since the beginning of the crisis China has been evaluating different pros and cons of taking different positions.On the one hand the intervention of Russia to Crimea challenges one of the norms that China has considered sacrosanct since the end of the Cold War, namely intervention in the domestic affairs of another country, due to its concerns about the Western restive regions and ethnic conflicts, including East Turkistan and Tibet. Due to these concerns, previously China was reluctant to support Russia's position in its intervention to Georgia in 2008. Now Beijing is less willing to make a quick decision in regard to this conflict. This is mainly because Russian intervention in Crimea can provide legitimacy for China's actions in some of the contested territories in South China and East China Sea. Consequently, some are suggesting that China will be able to act in order to follow through on its claim on the Senkaku Islands in the East China Sea and Spratly Islands in South China Sea by following the Russian example of resolving territorial disputes by the use of force. Moreover, Russian intervention also provides an opportunity for China to intervene in foreign countries under the pretext of "defending its nationals, ethnic brethren or to respond to an 'invitation.'"Given the increasing demographic influence of China in Southeast Asia and Central Asia, this would provide different opportunities for China to interfere in domestic politics of the countries in its region.