Unfortunately, in 2012 many states have passed laws which will suppressing voting by requiring ID, something the poor often lack. This change has happened despite multiple studies showing voter fraud is simply not an issue.
However, The Guardian has recently posited a theory for why Mitt Romney has refused to release his tax returns: possible voter fraud. Unfortunately, there aren’t a lot of facts to be found here, but the theory is certainly an interesting one. The damage being done by not releasing the returns certainly seems far greater than the damage of people simply being reminded that Romney is rich and doesn’t pay much in the way of taxes.
Of course, it’s possible the issue is really that they’ve been writing the horse off as a dependent.