According to Allan Gibbard, to judge that x is morally wrong is to express acceptance of a system of norms which permit feeling guilt for x-ing and resentment towards those who x. He wants to distinguish between accepting a norm and being in the grip of a norm.
With regard to the former, he write,
To accept a norm, we might say, is in part to be disposed to avoid it in unconstrained normative discussion, as a result of the workings of demands for consistency in the positions one takes in normative discussion. (74)
Question: What then is the difference between accepting a norm and being in the grip of a norm? Why does the distinction matter for Gibbard?