How were Fascist dictators able to rise to power in Italy, Germany, and the Soviet Union following WWI and helping to cause WWII?

First of all,
let us note that Stalin is not considered to have been a fascist dictator.  He was a communist
dictator.  However, the same general sorts of factors led to his rise to power as
well.

In all of these cases, dictators were able to rise because of chaos and
unrest of one sort or another.  In the USSR and Germany, there was unrest because of the poor
performances put on by the previous governments during the war.  In all three countries, there
was unrest because of economic conditions.  In Russia, this had to do with the general
backwardness of the economy and the oppression of the poor.  In Germany, it was because of war
reparations.  In Italy, it was because of worker strikes.

In all cases, then,
the dictators were able to rise because of chaotic times in their
countries.