Bilderbergers, the Iraq invasion, Alex Jones—the GOP senator has routinely flirted with America's paranoid fringe.This past summer, Rand Paul, the libertarian senator from Kentucky and a potential 2016 presidential wannabe, was the GOP's It Girl. The New York Times Magazine splashed his mug on the cover and asked, "Has the 'Libertarian Moment' Finally Arrived?" It noted that Paul possessed a "supple mind" and was a "preternaturally confident speaker." Washington Post political prognosticator Chris Cillizza pronounced Paul the "most interesting voice in the GOP right now," and Politico gave him the No. 1 spot on its list of the 50 "most...