Not sure really. Rand is relatively new on the scene. I think the idea was that he would take his Dad's base of support and expand it by moderating some of his fathers strong libertarian positions. It really isn't working too well, at least not yet, because part of Ron Paul's appeal (mostly to young people) was his peacenik, isolationist foreign policy - and Rand hasn't found a way to sell that with Republican primary voters.
I really do like much of what Rand Paul stands for, but he is too much like his father to me. And watching him try to thread the needle is difficult. I mean he has to take his Dad's positions and twist and shape them to something that almost no longer resembles the original policy.
Like foreign aid. Ron says "cut it all off, it's none of our business". Simple, straight forward, like it or not it is easy to understand. Rand however, has to placate a GOP primary population to even get the nomination, so you end up having him saying these really odd things like "cut off most foreign aid, MAYBE, POSSIBLY, even to Israel, because you see that will free up Israel to attack whoever they want, but I don't mean cut it off now, just sometime in the future if it becomes possible with Israeli support - to cut off the very aid they get from the US".
Rand needs to be his own man to get traction imo. Right now he is trying to be two things at once.