McCormick Taps Hedge Fund Riches in Bid for Pennsylvania Upset

David McCormick, once the leader of the world’s largest hedge fund, stood in a windswept parking lot in rural Schuylkill County, assailing Sen. Bob Casey, a Democrat whose name is nearly synonymous with Pennsylvania politics.

“Pennsylvania families, small business, seniors, farmers are all suffering from this economy and because of this weak leadership in Washington,” McCormick said at the Gilberton Power Co. in late September. Behind him stood workers in jeans and dusty boots, a decked-out campaign bus and a rust-stained cooling tower humming loudly.

Before running for office, the West Point graduate, combat veteran and businessman made ...