Reports from BBC News
and USA Today
indicate this may be a result of Stephen Colbert satirizing media reports which suggested that the popularity of candidates in the election could be determined by the amount of edits on their Wikipedia pages.
Several potential running mates of Romney had their Wikipedia pages locked down following Mr. Colbert's tinkering on his show 'Colbert Nation' of a suggestion made by TechPresident blog editor Micah Sifry's who said that clues could potentially be found regarding Romney's vice president pick on the free online encyclopedia. Colbert accordingly called on his viewers to "make as many edits as possible," to entries on possible running mates of Romney's.
Rob Portman, Paul Ryan's, Chris Christies and Rob Portmans Wikipedia pages were locked down, a message explaining that these pages were "protected due to vandalism." For the meantime anonymous users cannot make editorial edits on these pages.