In September, 1990, the United States, Great Britain, France, and the Soviet Union signed a treaty with the East and West German governments relinquishing all the occupation rights they had acquired under the terms of Germany's surrender at the end of World War II. On October 3, 1990, after more than 40 years of division, Germany was reunited as one nation. In December, Helmut Kohl's coalition government was elected in the first all-German elections since 1932. Following reunification there were numerous economic and social problems, mainly in the eastern states. Among those problems were a high rate of unemployment and increasing incidents of crime, including attacks by right-wing extremists on foreigners. The costs associated with reunification plagued the German economy during the early 1990's.
In national elections in 1994, the Christian Democratic Union and allied parties, who had governed Germany since 1982, were narrowly returned to power and Kohl was reelected by the Bundestag as chancellor. Meanwhile, during 1992-94 German military forces were sent to Somalia and the Adriatic Sea as part of UN missions. Controversy arose within Germany concerning the use of German armed forces in international military missions outside the jurisdiction of the North Atlantic Treaty Organization (NATO). In 1994 Germany's highest court ruled that, with Bundestag approval, German forces could be used in missions outside NATO areas.
After elections in 1998, the Social Democratic party (SPD) formed a parliamentary majority in coalition with the Greens, a leftist, environmental party. Gerhard Schröder, a political moderate within the SPD, was chosen as chancellor. The SPD-Green coalition ruled erratically, and state elections held in early 1999 led to the loss of its majority in the Bundesrat, the upper house of parliament. In fall of 1999, the long-planned move of the federal government from Bonn to Berlin was completed. Schröder was reelected in 2002.Germany and a number of other European Union members adopted the euro in 1999. The German currency was phased out by the middle of 2002. Angela Merkel of the Christian Democratic Union became the first woman chancellor in 2005.