Democrats have spent months praying for the liberal answer to Sheldon Adelson and the Koch brothers.

For the super PAC supporting President Barack Obama, there are plenty of potential recruits who can write multimillion-dollar checks - just few who have stepped forward.

With Republican outside groups on course to raise more than $500 million combined for the cycle, the pro-Obama super PAC Priorities USA Action is finding itself badly outgunned. Mega-donors either say privately they've been turned off by the White House's disdain for outside spending, or by the president's personal aversion to the constant care and feeding of contributors that such high-profile donors demand, a practice that his two most recent predecessors engaged in with flair.