As I argued here, the campaign finance system in this country is utterly broken, and Obama may have found the perfect way to skirt laws and raise a mind-blowing (and election-winning) amount of money. All you have to do is opt out of the public financing system, then raise as much as you can in small donations. If you're successful at it, apparently you don't even have to go through an audit. This is the first presidential campaign in which the candidates have raised more than $1 billion, led by Obama's $639 million- yet apparently the very fact that he opted out of the public finance system makes an audit less likely.
Politico. When the FEC determines whether an audit is necessary, it takes into account the amount the candidate collected--the more raised, the less significance each error carries, the commission reasons. Even an FEC complaint from the Republican National Committee raising concerns about fictitious donors and foreign addresses that snuck under the Obama campaign's radar probably won't trigger an audit.
If Obama had accepted public financing limiting him to $84 million for the general election, he'd be obligated to undergo such an audit. Instead, John McCain now faces a long and expensive accounting review that will analyze how he spent taxpayers' money after opting into the public financing system. McCain will use $9.4 million from his legal and accounting compliance fund to help pay for the investigation into how he spent his money.