To put it even more in my terms:
A power may be considered in two respect, in itself and with respect to its object.
Authority in itself is a power that proposes a good as superior. Political freedom takes many goods as equal. An authoritative act for political freedom is incoherent because authority in itself proposes a good as superior but political freedom takes many good as equal.
The proper object of authority is some particular good. Political freedom is not a particular good, but a capacity for many particular goods ambivalently. Political freedom is then no object for authority, like darkness is not an object for sight or silence for hearing. There is no seeing in the dark, no hearing in silence and no acting with authority for political freedom.