Why some would consider a 4-year presidential term a trick box. Belly of the Beast puts it succinctly:
My biggest worry is that the Democrats win the election, and then will be on seat when the crash occurs in this game of oil price chicken. The President will have very little effect on this situation when it occurs. And the American public will punish the current office holder severely when they can no longer afford to put gas in their SUV's.
Given how Californian voters were able to recall a governor, based on circumstances partly out of his control (Enron, dot-com bust, etc), anything may happen to a sitting duck POTUS during a future, inevitable, oil crash.