Rick's question about power over versus power with (or power over together with power with) reminds me a little bit of Tom's story about his student who felt like he could manipulate anyone by the end of 106. Tom seems really disappointed by the student's response but I wonder how much of that is really Tom's doing. As Rick noted, many of our current textbooks simply assume Aristotle's power over approach to rhetoric.
While I think that the power over approach is important to teaching rhetoric, I do think that Aristotle might open up some room for power with (although he doesn't specifically discuss rhetoric when he talks about this). For example, in chapter 13 Aristotle is discussing doing wrong. He states, "Thus, unjust and just actions are matters of being unjust and doing justly in two senses, either in respect to one defined individual or in regard to the community" (97). While I think Aristotle's example that follows (committing adultery = individual; not serving in the army = communal)is a bit limited, I think this part shows us the potential for a power with approach to rhetoric. That is, Aristotle is concerned with ethics in reference to the community. Since Aristotle is so binary-dependent, however, I think it is hard to read his Rhetoric for its open spaces. What the binaries do is make us look at rhetoric very narrowly (as power over instead of power with).
I, too, find myself wondering why a number of our textbooks insist on the power over approach to rhetoric. In light of the interest in rhetoric as a "power with" endeavor in our field, I find myself wondering why the composition textbooks have yet to catch up?