Since arriving in the Senate in 2011, Rand Paul has been probing here and there for issues of populist resonance. Audit the secretive, sinister Federal Reserve. Rein in those TSA screeners patting down little girls. In each instance, Paul (R-Ky.) has evoked the fear of oppressive government without tipping over into the paranoia of his father’s most dedicated supporters. It has been a diluted, domesticated, decaffeinated version of the ideology that motivated Ron Paul’s presidential races.