Most of the 500 wealthy conservatives gathered at a Southern California retreat this week know they want to see a Republican back in the White House, but many don't know what to do with the billionaire who wants to "make America great again." Republican presidential front-runner Donald Trump was not at the biannual Charles and David Koch-organized conference over the weekend, but he was a constant presence on the minds of many here at the seminar hosted by the billionaire executives known for their active role in Republican politics. The five candidates that the Koch's do prefer include Sen. Marco Rubio of Florida, former Florida Gov. Jeb Bush, Sen. Rand Paul of Kentucky, Sen. Ted Cruz of Texas and former Hewlett-Packard CEO Carly Fiorina. Although attendees at the conference are not monolithic in who they support in the primary, it appeared few in the crowd support Trump.