In liberal San Francisco this summer, he headlined a technology conference aimed at linking tech savvy Silicon Valley, and its money, with libertarian ideals and an effort to close the technology gap with Democrats, who were more technologically advanced in the 2012 presidential election than Republicans. Paul responded with an opinion piece in which he told Republicans that if they don't share their message with young adults and move out of their comfort zone, they'll never expand their base of voters. Nowhere has the effort to attract a new generation of Republicans been more fraught than in left-leaning California, where the GOP's registration has slid to 28.5 percent — just a few percentage points above the 21 percent of registered voters who are unaffiliated with any party.