Why does disfunction lead to a strong leader gaining power?

It gives then a chance to rise up and reunite , For example , after the Treaty of Versailles Hitler chose to rise to power and reunite Germany. Leaders will use anything to their devices in order to remain Im power .

can you tell me what is it

it would be  

germany had to pay all damages related to the war.

and i think

germany had to take sole responsibility for the war.