When Hillary Clinton said she was worried about insecurity in the workplace, Jeb Bush scoffed and promised to “hail” an Uber to go to his next event. Bush was supporting the “sharing economy” — and Clinton does, too, despite her reservations. The “sharing economy” is also being called the “gig economy,” because it’s changing the relationship between employers and employees, turning full-time jobs into part-time “gigs” -- liberating executives and workers, but without traditional worker protections. That’s raising questions about taxes and government regulation -- questions that presidential candidates are being asked. Uber is just one of the new companies that “poses a challenge to longstanding notions of what it means to hold a job,” according to Noam Scheiber of the New York Times.