Having a good discussion about ideology on Tumblr.
I'd should emphasize that this "ideology is contradiction" is part of what makes the Prequels so good.
As we know, most ideological systems are obsessed with a pre-lapsarian past, some Garden of Eden, where everyone was harmonious, before the bad guys ruined it with their excessive greed.
Now a critic can easily point to the factual details, and say "no the 1950's had plenty of problems, there were racial tensions and Cold War paranoia after all and..." as a way to empirically dismantle American traditionalist ideology. And golden pasts are so rare in our history that you could be sure to always find some way to context their details, as a way of critiquing a particular ideology (be it racist, or Capitalist, or Nazi, or liberal ideology.)
But, by operating purely in fiction, the Prequels attempt something much bolder. They say even in the most convenient fantasy of our minds, this myth of a harmonious past is unworkable. Fans dreamed about how awesome the Republic was for twenty years, but since it necessarily had to fail, then it could not have been that great. There must have been serious problems if it became the Empire.
(Or maybe Lucas intended to draw a perfect past, spoiled only by one mischievous Sith Lord. It just so happens that depicting this in detail was impossible, and so the attempt to do so revealed its internal contradictions.)