"In 2010, Romney voted for Republican Scott Brown in Massachusetts’ special election to fill the Senate seat vacated by the late Ted Kennedy.
To prove his Bay State residency, Romney claimed that he was living in his son Tagg’s unfinished basement – which seems unlikely for a quarter-billionaire with multiple houses of his own.

If Romney was lying about his residency, it would constitute voter fraud, a crime punishable by up to five years in jail.
Commission of that particular felony would be highly ironic, given the extreme lengths to which Romney’s own party has gone to root out alleged election fraud.

Some observers, like M.S. Bellow Jr. of The Guardian, have speculated that Romney refuses to release his 2009 tax return because it lists an address other than Tagg Romney’s Belmont, Massachusetts home.
The vote-fraud story has mostly gone unnoticed by the mainstream media, however."
Henry Decker
http://www.guardian.co.uk/commentisfree/2012/aug/17/mitt-romney-tax-returns-voter-fraud-theory