There are periods when the international system undergoes radical shifts in a short time. The last such period was 1989-1991. During that time, the Soviet empire collapsed. The Japanese economic miracle ended. The Maastricht Treaty creating contemporary Europe was signed. Tiananmen Square defined China as a market economy dominated by an unchallenged Communist Party, and so on. Fundamental components of the international system shifted radically, changing the rules for the next 20 years.