“By the late 1960s, the stage was set for detente …. For detente to succeed, the West would have to accept an ideologically divided Europe for the foreseeable future. / For the German nation, this meant a divided country, locked in separate spheres of influence and in two military alliances. In practical terms, it also made Germany the most likely future European battlefield, as NATO and Warsaw Pact troops faced each other across the inner German frontier. / … In the end, Brandt’s strategy was effective, …Every player came away believing enough had been gained for concessions given to justify support for the final package. By 1973, the main Ostpolitik objectives had been achieved. / … On October 3, 1990, … the collapse of the Soviet Union permitted German unification. Because of the changes that Brandt brought about in inner German relations, the road ahead, though rocky, was at least open./ … Could Ostpolitik have been implemented more efficiently? Probably not….”.
Source: Willy Brandt and Ostpolitik, National Defense University National War College Fort McNair in Washington (1998) http://www.dtic.mil/dtic/tr/fulltext/u2/a437169.pdf