Things we don\textquoterightt yet understand about solar driving of the radiation belts.

This commentary explores how close we are to predicting the behavior of the radiations belts - the primary science objective of NASA\textquoterights Van Allen Probes mission. Starting with what we know or think we know about competing sources, enhancement, transport, and loss, I walk through recent papers that have improved our understanding and then focus on flux dropouts as one particular yardstick of success. I mention a new paradigm for electrons and the importance of reliably matching models and observations for different solar inputs. Although the case for prediction remains a work in progress, there are encouraging signs of progress.