In the above graph, the diagonal represents Obama's expected vote totals, on the basis of the infamous January 6th CNN poll. For the bottom portion of the line, the small and medium sized towns, the hand counted vote totals are distributed around the line, above and below. That's normal. He's above expectations in some places, and below in others. For the same portion of the line, his machine counted vote totals are systematically below the line. This is not normal. It means that his hand counted votes and his machine counted votes are not behaving the same way for same-sized locations.
In larger towns, at the top part of the line, the distribution of machine counted vote around the expected line becomes fairly normal again. Some vote totals are above expectations, some are below. This is important. It means that a test of statistical significance is not likely to detect the deviation from normality in the smaller locations. The larger locations, with their higher vote counts and normal distribution will overwhelm the smaller locations. In other words, most tests of significance will be blind to the fraud.
Ok, so Obama lost some machine counted votes. But a fraud in which the combined vote totals don't match the overall number of votes cast is not a very subtle fraud. Where are the missing votes? Giving them to the winner is equally unsophisticated. In fact, it is clear that Clinton really did beat the polls. There is no real difference between her hand counted and her machine counted votes.
If we look at Edwards' vote totals however, we see a mirror image of the Obama pattern. In low and mid-sized towns, his machine counted vote totals are systematically above the expected line, while they abruptly go back to it for the larger locations.
Giving the votes to the third place guy who has no hope of winning is clever. Subtle. In fact, that is exactly what I would do. I'm devious that way. Here's another devious thing I would do. I would create a big stinky red herring to cover the subtle scent of my operation. For example, I might start loudly claiming that tens of thousands of votes were taken away from Ron Paul. I would make the story easily debunkable, and I would make sure that it immediately associates any talk of fraud in New Hampshire with the fringe, kooky element.
A subtle fraud, involving just enough votes to generate the desired outcome, a pattern that flies below the statistical significance radar, and a big stinky red herring. A job well done.