In this case it might make sense that "some other candidate" is so high (angry neocons).
Eh, most Republicans are just being like Hillary supporters and would probably just hold their noses and vote Paul if he won. Some wouldn't, but they are aren't an especially large demographic, since there are Democrats who would be voting Republican based on foreign policy/drug laws.
What really makes the difference is that all the other Republicans lose indies to Obama while Paul wins them by 10%. If he won the nomination and that continued, he would crush Obama easily.
