Sanders is a candidate who presents himself less as a personality than a conduit for a movement. And in the Bernie bubble, Ocasio-Cortez is seen as the future of the movement embodied. What makes her so effective as a surrogate, beyond her star power, is that if you campaign on electing a movement rather that a person, there’s no difference between hearing the message from the 78-year-old white male candidate or his 30-year-old Latina supporter. The perception among her supporters is that a vote for Sanders is also a vote for Ocasio-Cortez to continue her rise.