This paper shall set out to examine the role in which institutions play when influencing states actions on the global stage, but first we should understand what institutions are and where their prominence came from, and why they have not always been key actor on the global stage. In order to do as such this essay will first define what institutions are then look at what are the primary institutions that affect states actions in IR and focus on these as to not spread the goal of the papers objectives too thinly. It will then look at case studies and real life events where institutions have affected the behaviour of states for the better, this will mainly be focused on the role of international law and institutions such as the EC, international Energy Agency, EU, UN and NATO in addition to what power they can wield as to ‘keep states in line’ and acting in the interest and benefit of the many rather than the few. The penultimate part of this essay in order to keep a fair, balanced and holistic view of the role of institutions will be looking at the counter arguments and events of where they do not affect states on the global stage or fail to live up to their objectives, this will be based on the case study of NATO’s and the EU’s involvement in Ukraine. The finial part shall weigh up what this paper has covered and based on the arguments give a clear analysis of how affective institutions are, whether or not they do have a large impact on states and how they do this and if not how they can improve for future influence. Institutionalism can be defined as “a set of rules that stipulate the ways in which states should cooperate and compete with each other”, these rules once accepted by states tend to form international pacts or “mutual acceptance of higher norms.”, (Scott, 1995). Institutions emerged as primary actors on the global stage in the early 1990’s as the Cold War came to a close, in a post-Cold War era the world faced new issues that realism failed to effectively address, it was proclaimed that the ‘end of history had occurred’ (Nau, H. 2007). Before the end of the cold war Realism was straight forward and explained the world politics in simple terms with states as the main actors and balance of power politics the primary tool, when this ended Europe based policy makers wanted to strengthen security by empowering institutions as main actors on the global stage, Robert Keohane even stated that “institutions are key to maintain peace in Europe”. Institutionalism has three main components; Collective security, Liberal institutionalism, and Critical theory. Collective security is the concept that states bound tougher by force or circumstance whether it be regional such as NATO, political or other connecting points between them understand and accept that the security of one state is to the benefit of all states within that connecting parameters (Goldstein, J. and Steinberg, R. 2010), i.e. if one European state is attacked by an external force then the rest would react and come to aid that state with the understanding the same would apply if it were to happen to each of them. This binds states to become less isolated in terms of security and makes each state a larger force, one not worth attacking (i.e. a zero-sum game) and so have much greater deterrents than any one state standing alone which unarguable is an improvement upon their security (Bull, H. 2002). In addition it means that states become more reliant upon one another and this in turn creates greater trust between states rather than the ‘everyone even your allies can turn on you at some point down the road’ attitude that realism school of thought championed during The Cold War (Baldwin, D. 1993). The first official attempt of Collective security was the League of Nations which given World War II doesn’t fall under the favourable example in support of collective secu