Cue the sharp, staccato violin music, the wail of ghostly sopranos, and M. Night Shyamalan.  Is it possible that the vaunted billion-dollar campaign of Barack Obama might stumble into second place to Mitt Romney on fundraising?  Chris Cillizza writes at the Washington Post that the scenario of an incumbent falling short in official fundraising to his challenger is not just possible, but looks less and less like a long shot:

What’s abundantly clear is that Obama won’t have the massive fundraising gap over Romney that he enjoyed in the 2008 contest against Sen. John McCain of Arizona.

In that race, Obama raised an astonishing $771 million while McCain brought in $239 million — a total that included roughly $85 million in public financing funds for the general election. (Obama opted out of public financing.) For you non-math majors out there, that means Obama collected (and spent) three times as much money as McCain, a huge gap that almost certainly put the Democrat over the top in places such as Indiana and North Carolina and cushioned his margins in other swing states such as Florida and Ohio.

There is a zero percent chance that Romney will follow McCain’s lead and take public financing. And even though he has spent most of this election cycle running in a competitive and splintered GOP primary, Romney raised almost $100 million through April. …

Add it all up — and throw in a pledge from the leading conservative super PAC to spend better than $200 million— and it becomes possible that Obama, the single greatest fundraiser in the history of American politics, might get outraised (and outspent) between now and Nov. 6.

What about the super-PACs?  After all, the Left has an abundance of big-ticket donors who could push Obama forward through third-party groups.  They could … but so far, they aren’t:

The pro-Barack Obama super PAC Priorities USA Action is still struggling to keep up with GOP super PACs preparing to unleash millions of dollars in independent advertisements.

Priorities USA Action raised $1.6 million in April, according to federal records released late Sunday. It’s the smallest haul the group has pulled in since the meager $59,000 the group raised in January.

The group raked in $3 million less than the pro-Mitt Romney super PAC Restore Our Future raised in April, even as the GOP group reported its worst fundraising month so far this year.

The bulk of Priorities USA Action’s cash in April came from labor groups. The National Air Traffic Controllers Association PAC contributed $1 million; another $250,000 came from the United Association of Journeymen and Apprentices of the Pipe Fitting Industry. Both union checks came on April 30, the last day of the filing period.

Including the two labor groups, the super PAC received only nine donations of $10,000 or more in April. Top donors included Joseph Kiani, chairman and CEO of Masimo Corp.; Ariel Capital CEO John Rogers; and television executive Michael King.

Unions will fill the gap through their own efforts, but that ability may be limited in 2012.  Big Labor has poured millions into Wisconsin’s recall and Supreme Court elections over the last year, and so far have come up empty.  They have two more weeks to go before Scott Walker defends his office in the gubernatorial recall, but the race looks as though it will slip through the unions’ fingers.  Unions are also fighting in Indiana and Arizona over right-to-work and other union-limiting legislation passed this year.  They will put millions into Obama’s effort, but they may not have the resources to be game-changers in this cycle.

BuzzFeed reports that big-money donors have begun to disappear from the Obama campaign, and that had a big impact in April’s numbers:

Obama’s campaign took in $25.7 million, after raising $43.6 million in conjunction with the Democratic National Committee. That represented a drop from the $35 million in receipts the campaign saw in March on $53 million raised by the joint fundraising effort.

Most of Obama’s drop is attributable to a decline in contributions of more than $500, which fell by more than $9 million. Many of Obama’s top donors have already hit the legal $2500 maximum to the campaign, which — along with an apparent failure to recruit a new cadre of wealthy supporters — may account for the decline.

In other words, the Obama fundraising effort has already hit its high-water mark.  They will continue to get smaller donors, but the larger donors have either maxed out or have abandoned the incumbent.    In contrast, the Romney campaign has just gotten started.  A few more months like April, and Barack Obama might suddenly rediscover his love of public financing for elections.