U.S. governments have been questioning the contribution of the NATO alliance for the last two decades. Although the U.S. pioneered the enlargement of the alliance, it mostly prefers to act unilaterally in its security policy, which creates problems for NATO. The absence of American leadership and the lack of interest by American politicians are the most important problems of the alliance besides decision-making, budgeting and coordination. For many American politicians, NATO today serves neither as a multilateral platform nor as a collective security organization. Unilateral American foreign policies have been destroying the collective logic of the alliance since the U.S. government prefers not to discuss security strategies in multilateral platforms. U.S. President Donald Trump, who describes the new strategy as "America First" – if not "America Only," emerged as a symptom of this new thinking in foreign policy. For many American politicians and authorities, NATO has begun to lose its rationale and strategic outlook. They have lost their confidence in NATO and consider the alliance a burden since they think that the alliance does not serve the interests of the U.S. anymore. For instance, former U.S. President George W. Bush and his Secretary of Defense Donald Rumsfeld described the post-communist period Central and Eastern European countries as "the new Europe" and Western Europe countries as "the old Europe." They attached greater importance to "the new Europe," i.e. the newer members of NATO located in the central and eastern part of Europe. That is, the old members of the alliance, including the Western European members and Turkey, lost their significance in American strategic calculations. Similarly, both President Barack Obama and Donald Trump have called European NATO members "free riders" and questioned their membership. Furthermore, President Trump even declared the NATO alliance "obsolete" during a NATO summit meeting in 2018. There are several reasons for this new American perspective of NATO. First, the meaning of the NATO alliance was changed after the collapse of the Soviet Union and the communist bloc. There are too many new types of challenges and security phenomena such as international terrorism, migration flows, the fight over energy resources, cyber threats, hybrid threats, hard/soft threats, regional/global threats and operational/tactical/strategic threats. However, there is a lack of understanding about a common threat perception. Mainly due to the complexity of the threats, definitions and perceptions of the threats, enemies and adversaries have also changed. Eventually, the lack of consensus about the definition of threats ended with important uncertainties about the threats and challenges to the alliance and to member states. As a clear example, the U.S. as the leading member has considered the People's Protection Units (YPG)/Democratic Union Party (PYD) as their main ally in its fight against terrorism, while another NATO member Turkey considers the same organization a central threat to its national security and territorial integrity. Although all sides know that the YPG/PYD is the Syrian branch of the PKK, which is a terrorist organization not only recognized by Turkey but also by the U.S. government. Second, the security perception, expectations and priorities of NATO members have changed in the post-Cold War period. Although all members still believe in the necessity of the alliance to a certain extent, there is no common threat perception and therefore no cooperation efforts among the alliance members. The security policies of member states contradict each other. For instance, while Turkey perceives threats mainly emanating from the chaotic Middle East and recently from the Eastern Mediterranean, many NATO members still perceive Russia as the most imminent threat. Following a unilateral foreign and security policy, the U.S. government doesn't want to rely on international institutions, including NATO. Furthermore, the U.S. has been fighting against the system that it established after World War II. At a time when the U.S. government decided not to undertake its responsibilities as the global hegemon, NATO transformed itself from a trans-Atlantic alliance into a global military coalition. The alliance initiated out-of-area military operations in the wake of the Cold War; NATO even utilized "the responsibility to protect" mechanism in out-of-area such as Kosovo and Libya. While the U.S. unilaterally undertook the responsibility of protecting its allies against the Soviet threat, today it is hesitant to play the same role. In other words, the U.S. government has a paradoxical approach toward NATO. On the one hand, it considers the alliance obsolete and irrelevant against the new challenges. The U.S. does not show sensitivity to the security concerns of other member states. On the other hand, its calls other member states to contribute more to the alliance. Last but not the least, the new American and NATO security perspectives do not converge on the definition of threats and security challenges. There is less harmony between member states in the definition of threats and the use of instruments. However, no NATO member wants to lose the deterrent power of the alliance during a shifting balance of power on the global level. However, it is necessary to maintain the deterrent power of the alliance by increasing the harmony among the member states since NATO is not only a military alliance only but also a political organization based upon certain principles. Naturally, it is expected that the strongest and the most important member, the U.S., respect these principles. This requires the U.S. to abandon its unilateral security policy and to act on a multilateral platform, specifically the NATO alliance. [Daily Sabah, 12 June 2019]