There are three main global transformations that brought the world order on a new stage - the stage that rules the current post-modern era. However, it started more than ten years ago, the main predominant turn happened at the very beginning. To list those are: the collapse of the Soviet Union; terrorism; and the appearance of 'rouge' states.
To point out, the prior one, which gave the starts to all others was the collapse of the Soviet Union. After the official Gorbachev's speech of dissolution , the world had stopped to be bipolar but has not yet become either multipolar nor, of course, unipolar. With the fall of the Soviet Union the United States has nobody and nothing to struggle with because its enemy (USSR) for at least forty years was an antagonist and the absolute opposite of it. Even though that the soon collapse of the Soviet Union was expectable and desirable at that time, the fact of it became a big shock to the whole western hemisphere.
The whole US politics, especially the foreign one was oriented to the rival against the east. Now it had to turn its politics on the situation of a sole dominance, which showed itself as a very hard task to realize because the US politics was based on the identification, making strategies and then implementing various policy models aimed to struggle with the enemy.
Moreover, if the world order before the collapse of the Soviet Union could have been described by such concepts as: 'threat perceptions', 'deterioration', 'arms-race', 'total conservatism', 'East and West', 'modern era' and 'realism', today it can be defined by such slogans as 'national missile defense', 'globalization', 'liberalism', 'North and South', 'post-modern era', 'terrorism', 'rouge states' and "clash of civilizations and others.
To go back to the...