In the decade after the construction of the Wall and the division of the country in East and West, the first SPD-led government in post-war Germany adopts a controversial policy of Ostpolitik, a new direction in foreign policy, which sought to overcome the effects of division in Germany and Europe by accepting the reality and working within its confines. The main tenet of the policy is "Wandel durch Annäherung" or change through rapprochement. Under this policy, West Germany relinquishes its claim to sole representation for all of Germany.

At the same time, Willy Brandt pursues a policy of detente with Eastern Europe and reconciliation with the countries that had been occupied by Hitler. In 1970 several accords are signed, including ones with the Soviet Union, Poland and Czechoslovakia. Brandt is criticized by opponents of his Ostpolitik who saw the policy as "betrayal". The attacks reach a climax when Brandt, in Warsaw in December 1970, makes a gesture that goes around the world: He drops to one knee before the memorial to the insurgents of the Warsaw Ghetto Uprising.

In 1974, when it was discovered that Günter Guillaume, a spy for the GDR, had made his way into the tight circle of the chancellor's closest advisers, Brandt accepts the consequences and resigns.