Okay, fine, the possibility. In order for me to be able to accept the possibility, I would need to first assume the existence of god (or at least satan), that satan would have an interest in influencing political events in the United States, and that he would have anything at all to gain from the ordeal. Unfortunately for him, and you, I am atheist, so it takes a fair amount of open-mindedness to even consider the possibility of a creator of the universe. This is something that I am in fact open-minded enough to consider "possible", even though I do not believe it, and if the topic is broached will argue the point that there is no satisfactory evidence for the existence of such.
In other words, open-mindedness to Santorum's idea requires several prerequisites to be accepted - ones which I'm willing to consider... but unless I accept them as true, I cannot be open-minded to the idea that satan is trying to destroy America with abortions.
That, and the entire argument smells of bullshit even from a Xian perspective.