Yes, well spotted - the two party system definitely employs the same mechanic: all the evils are projected out to the 'enemy', and all the wrongs in their own group are ignored. This provides group cohesion and allows them to avoid cognitive dissonance and taking responsibility for the results of their own choices.

If there were more than two viable parties, or, god forbid 3-4 viable parties like in many European countries, this would be near impossible to make work. You cant vilify 2-3 other groups as the 'ultimate' evil at the same time...