One of the root causes of of the Weimar Republic's downfall was the inability of the established parties to get over their constant squabbling, leading to the state pretty much being paralysed. This, combined with an economic crisis, created the perfect environment for fascists to thrive and ultimately destroy the inept state from within. Unfortunately this is repeating, the rise of the AfD is no surprise, and in order to see what this can lead to if left uncorrected, we only have to look back in history roughly 90 years.