If you read my blog, you know I think the popular guy gets the most money, rather than the most money buys the vote.
I still maintain that is correct for a presidential general election. But discussions I have had with other people have led me to realize that it might not be the case for all elections.
I believe the Levitt and Dubner (Source = Frekonomics author's study) claim that doubling the money gives you a 1% advantage. So the effect is small, and more than outweighed by random real world events (Bush's recession destroyed McCain's chances). If you spend 16x the money the other guy does, you only get a +4% advantage, that is a lot of money for a small bonus. Typically a presidential election one candidate can't get more than twice the money of the other guy - and then only if he was already far more popular.
But Superpacs have changed that a little bit, and more importantly, it is only true for the general presidential election.
What applies to national general politics does not always apply to lesser races. You can't buy a presidency, but if you are rich enough, you can buy a mayorship. Consider Romney, with $250 million. A mayor's race may cost less than $100,000, and Romney could easily pay $6.4 million, earning him an +6%.
Also, as Romeny -Santorum has demonstrated, organization costs money and it can keep you off the primary ballot in certain states. Some would say that if Santorum can't get the money and organization together for the primaries, he can't win a general election. I reply that to the winner of the primary gets the best support from the establishment, and Santorum would be flooded with more competent people and more money if he did in fact win the primary.
I continue to believe that money can't buy a general presidential election, but local elections and primaries in particular are a different story. It is possible to buy them.
Yet one more reason why the state and local governments are far more corrupt than federal governments.