Everything is a problem. It's not that hard to find the real politics, however. Its a question of looking in the right places. Of course, power has a rhetorical form, on this i think we are agreed. But not all rhetorical forms in the world are equally interesting or significant.
Power passes through some.
Others just play with the signs. If we were to look seriously at an issue like national debt, for example, we might find that it is not without rhetoric. Accounting, after all, is conventional, which is to say, it has a rhetorical dimension. But one that has real effects. I don't know why you are citing Althusser at me, however.