Three other factors suggest that the idea of Obama as a billion-dollar candidate in 2012 is not so far-fetched.

First, he collected $750 million while running as a senator. He’ll now be running as a president, which should allow him to clean up financially to an even greater extent, thanks to the power of incumbency.

Second, the continued development and maturation of Internet fundraising over the past four years means that the $500 million – yes, you read that right – that Obama raised online in 2008 could well be topped in 2012, noted Ben Ginsberg, a top Republican lawyer who served as an adviser to former Massachusetts governor Mitt Romney’s 2008 presidential bid.

Third, the growth of a shadow Republican Party of outside groups – epitomized by American Crossroads, which spent $70 million on the 2010 midterms – should help fuel Democratic donations to Obama. (It remains unclear whether a Democratic-aligned outside group – or groups – will form to siphon off some of those donations.)