This is not rhetoric. We're so used to over-the-top political rhetoric (think Paul Martin, folks) that we might pass on this. In the case of Tea Party people, they really do think their government has been captured by alien forces. This is, of course, disturbing for a democracy. The division of citizens into us and them is not something that should happen in a democracy. Indeed, it is antithetical to the very ideal of democracy. Have no doubts about it, however, they do want to take "their" government "back."
Note, too, what this means: they once had it. One assumes that he is here referring to Bush II. My view is that these kinds of statements are likely just the first of many we will hear over the next two years. They are divisive, to be sure, and disruptive and alienating. From whom, we might ask, are they taking their government back? It was elected by other Americans.