I very much doubt either case has anything to do with fraud, just a large enough sample size of precincts in very skewed districts to find cases of everyone voting one way. Here's my basic take: No one is dumb enough to do vote stuffing (or vote nullification) to the tune of 100%. If you are going to rig an election (or, say, a multiple choice test), you do it in a way that looks plausible. No cheater gives themselves a perfect score, because it may raise suspicion. Sure IL has a history of voter fraud (most famously in 1960, in which IL was in play and may have cost Nixon the election), but why stuff ballots in 2012 when IL is meaningless in the electoral college? Obama won IL by 16 points; no amount of ballot stuffing can produce a 16 point victory, because the amount needed would be impossible to cover up. Vote rigging can only work in a close election (see, for example, FL c. 2000). These logical problems make me doubtful that anyone would risk going to jail for literally no gain. The cost-benefit doesn't add up.