Donald Trump should have seen it coming. He arrived on May 25th at the Libertarian Party’s national convention in Washington, DC, hoping to expand his support, but the crowd mostly responded with boos. Attendees lacked enthusiasm for a protectionist who added $8.4trn to America’s national debt. They also spent the weekend squabbling among themselves. After losing presidential races for more than half a century, the Libertarian Party is facing an identity crisis.