AUSTIN, Texas — Tuesday evening after Sen. Rand Paul (R-KY) announced he was running for president, dozens of “#LibertyKaraoke” events all across the country helped the new candidate recruit hundreds of volunteers and kickstart his campaign fundraising. Liberty Karaoke was originally conceived as a casual fundraiser targeted to young libertarians, to gather regularly for karaoke, network with other like-minded friends, and make online donations to liberty-oriented candidates. The concept had successfully raised thousands of dollars for Rep. Justin Amash (R-MI) and Rep. Thomas Massie (R-KY), but Paul’s entrance into the presidential race inspired supporters to take what had been a...