Jim Geraghty offers an interesting report that, if verified, could be quite significant:
Today, news out of New Mexico, the state GOP looked at information for 92 newly-registered voters in one district, and found 28 had "missing or inaccurate Social Security numbers or birth dates. In some cases, more than one voter was registered using the same Social Security number. In others, people who the Republicans said had no Social Security number on public record were registered." All of these are of individuals who have already cast ballots in the June New Mexico state legislative Democratic primary.
The key element of the story, if confirmed, is that these individuals actually voted, so that this would not be a case of simple registration fraud, but actual vote fraud. Another possibility is that the individuals in question were all eligible voters who simply submitted sloppy or inaccurate registration forms. We'll have to see. The Santa Fe New Mexican has more here.