Look like there is evidence of sizeable voter fraud.

In a forthcoming article in the journal Electoral Studies, we bring real data from big social science survey datasets to bear on the question of whether, to what extent, and for whom non-citizens vote in U.S. elections. Most non-citizens do not register, let alone vote. But enough do that their participation can change the outcome of close races.

How many non-citizens participate in U.S. elections? More than 14 percent of non-citizens in both the 2008 and 2010 samples indicated that they were registered to vote. Furthermore, some of these non-citizens voted. Our best guess, based upon extrapolations from the portion of the sample with a verified vote, is that 6.4 percent of non-citizens voted in 2008 and 2.2 percent of non-citizens voted in 2010.

Because non-citizens tended to favor Democrats (Obama won more than 80 percent of the votes of non-citizens in the 2008 CCES sample), we find that this participation was large enough to plausibly account for Democratic victories in a few close elections. Non-citizen votes could have given Senate Democrats the pivotal 60th vote needed to overcome filibusters in order to pass health-care reform and other Obama administration priorities in the 111th Congress.

We also find that one of the favorite policies advocated by conservatives to prevent voter fraud appears strikingly ineffective. Nearly three quarters of the non-citizens who indicated they were asked to provide photo identification at the polls claimed to have subsequently voted.