An unprecedented amount was spent by outside groups in an effort to influence the 2012 campaign, though generally the candidates with the most super PAC funding were defeated Election Day. In the Presidential race, those supporting Romney spent over 300 percent more per vote, but produced over 3 million votes less than President Obama did.
While not the most expensive campaign by the amount of money spent total, the most expensive race per vote was the Nevada Senate race; Shelley Berkley spent nearly twice as much as her opponent Dean Heller and still lost. Worth noting in all of these cases, most of the funding money was used to attack the opponent rather than support their candidate.
Source: Projects.Propublica.org
