This is a challenging question if you don't pay that much attention to politics.
In my opinion, neither Camus or Voltaire would vote at all. Camus is an absurdist, so he doesn't believe that there is no meaning in life. He would feel like his vote wouldn't matter. Voltaire sees little sense in society and he would feel like his vote would be for the lesser of two evils. So he would just not vote.
However, I can see Voltaire voting for Obama. In Candide, he satirizes the upper class and seems to be more supportive of the average/middle class, which is parallel to Obamas campaign.
