What will Mitt do?
Take, "What will Obama do?" and subtract "What will Mitt do?". That goes you the difference.
To put it in numerical terms, Obama does -9 for the cause of life. Mitt might do 3. |-9 - 3| is 12.
That's the difference, in my poorly-constructed numerical analogy.
Think of all the children who will die when Obama cracks down on peaceful sidewalk counsellors, making that a federal crime. Would Mitt do that? You know the answer.