Was it unfair for Gibson to expect that Palin know what the Bush Doctrine is?

The Bush Doctrine (policy of pre-emptive strikes even when threat is not imminent) represents one of the most profound shifts in US foreign policy, one that is still very controversal. Palin was not aware of what the Bush Doctrine was, nor would say she supports it or not even after Gibson explained it to her. Was that an unfair expection of a candidate for vice president?