The key political difference between east and west Germany is that the disintegration of the mainstream political parties is far more advanced in the east. This is one of the main reasons the AfD performs best in the east. Unlike in the west, the traditional parties have never had a stable electoral base in the east. Election successes have been largely down to the popularity of individual leaders. In the west, the traditional parties are still able to rely on some form of voter loyalty. But these loyalties have been breaking down quickly in the west too, as the broader decline of the SPD illustrates.