Beyond super PACs, other sources of money are at play, including groups like Karl Rove's American Crossroads, which between its super PAC and its nonprofit affiliate Crossroads GPS, has brought in a combined $99.8 million for Republican candidates since the start of 2011.

Public funding in the general election comes in the form of a grant given to a major party nominee if the candidate agrees not to raise or spend outside funds. But with this year's numbers, it seems pretty likely that both Romney and Obama with opt out of public financing.

No general election candidate had ever refused these funds since the program began in 1976, until Obama made the leap in 2008. John McCain accepted public financing.

Given McCain's affinity for campaign finance reform, Allison said it was "awkward for him to raise money in big donations" but that this time around "you wont see any such compunction" from the Republican nominee.

And if the race is close, Romney might be able to tap another source of funds: his own bank account. After all, candidates can fund their own campaigns, and the former Bain Capital CEO is estimated to be worth as much as $264 million.