Regional Conflicts Generate New Problems of Nuclear Control The Cold War that weighed so heavily on the world after World War Ⅱ ended with the fall of the Berlin Wall in 1989, unification of East and West Germany in 1990, and the demise of the Soviet Union in 1991. Many East European countries now started to draw closer to the West. Russia, too, sought democratic and market reform under the leadership of President Boris Yeltsin. Despite the United States' victory in the Cold War, the global situation did not become more stable. Without the constraints imposed by the stand off between the USA and USSR, regional conflicts based on nationalism, religion, and ethnic rivalries flared up in various places.     The Gulf War broke out in 1991. Middle Eastern instability, rooted in the Palestinian conflict, kept the world in fear of war.   The Daily Threat of Nuclear Weapons and War     This was the period when Japan experienced two biochemical attacks by the Aum Shinrikyo Cult: the sarin incidents in Matsumoto (1994) and the Tokyo subway network (in 1995). There was rising concern that terrorists might also use nuclear and other radioactive weapons, other countries besides the established nuclear powers would increasingly gain nuclear capability, and anti-social segments might resort to nuclear blackmail.