Of all the others, I think Ron Paul would've not only done it, i think that he would've gone so far as dismantle the NSA complelely (blocked by congress ofcourse).
//EDIT: But these "would've, should've"-statements are pretty much pointless. What is more interesting is what is being done right now, which seems to be nothing.
Eh can't see that as productive. Eliminate your country's best SIGINT agency and hope nothing ill comes of it in the end ? Not disagreeing that Intelligence agencies be kept on a tight leash though