I don't see rhetoric as being a persuasive tool to bring people to the other side. I see rhetoric as a trait of being able to communicate your ideas in a way that catch other's attention and allows them to understand. Just because somebody speaks well does not mean that they are going to change attitudes towards the topic being defended. People are naturally stubborn and just don't change their minds or hush because somebody can communicate better than them. Good rhetoric can be used in any situation, but it doesn't mean that the speaker is right.
For example, if a well spoken individual gives a long speach filled with attention getting words and has the whole crowd eating out of his hand, he will most likely not be able to convince them that jumping off the empire state building will not kill them. While another individual that gets up and states in a hick voice with awful rhetoric will be able to convice people that they will die if they jump off of the building. So while rhetoric helps to grab others attention, I don't think it is that persuasive.
