Obama’s hoping what happened with Katy Perry in Vegas doesn’t stay in Vegas, but spreads to the whole state of Nevada to give him an edge. The president and the pop star joined forces into the wee hours on Wednesday night for a campaign rally concert in the battleground state, where they pumped up a crowd of 13,000. The sexy singer adapted her signature style for the event, turning her body into a ballot in a tight white latex dress printed with the names of the candidates.