Butler’s theory of citationality is a core feature of her work post Gender Trouble. It’s a difficult concept but exremely productive. Here is a taste of it from her 1993 book Bodies That Matter. I will quote at length because every sentence is mind numbingly expansive.
To take up the political signifier (which is always a matter of taking up a signifier by which one is oneself already taken up, constituted, initiated) is to be taken into a chain of prior usages, to be installed in the midst of significations that cannot be situated in terms of clear origins or ultimate goals. This means that what is called agency can never be understood as a controlling or original authorship over that signifying chain, and it cannot be the power, once installed and constituted in and by that chain, to set a sure course for its future. But what is here called a “chain” of signification operates through a certain insistent citing of the signifier, an iterable practice whereby the political signifier is perpetually resignified, a repetition compulsion at the level of signification; indeed, an iterable practice that shows that what one takes to be a political signifier is itself the sedimentation of prior signifiers, the effect of their reworking, such that a signifier is political to the extent that it implicitly cites the prior instances of itself, drawing the phantasmatic promise of those prior signifiers, reworking them into the production and promise of “the new,” a “new” that is itself only established through recourse to those embedded conventions, past conventions, that have conventionally been invested with the political power to signify the future.
It is in this sense, then, that political signifiers might be avowed as performative, but that performativity might be rethought as the force of citationality. “Agency” would then be the double-movement of being constituted in and by a signifier, where “to be constituted” means “to be compelled to cite or repeat or mime” the signifier itself. Enabled by the very signifier that depends for its continuation on the future of that citational chain, agency is the hiatus in iterability, the compulsion to install an identity through repetition, which requires the very contingency, the undetermined interval, that identity insistently seeks to foreclose. The more insistent the foreclosure, the more exacerbated the temporal nonidentity of that which is heralded by the signifier of identity [I have no idea what this means]. And yet, the future of the signifier of identity can only be secured through a repetition that fails to repeat loyally, a reciting of the signifier that must commit a disloyalty against identity— a catachresis — in order to secure its future, a disloyalty that works the iterability of the signifier for what remains non-self-identical in any invocation of identity, namely, the iterable or temporal conditions of its own possibility.
For the purposes of political solidarity, however provisional, Žižek calls for a political performative that will halt the disunity and discontinuity of the signified and produce a temporary linguistic unity.
The failure of every such unity can be reduced to a “lack” with no historicity, the consequence of a transhistorical “law,” but such a reduction will miss the failures and discontinuities produced by social relations that invariably exceed the signifier and whose exclusions are necessary for the stabilization of the signifier. The “failure” of the signifier to produce the unity it appears to name is not the result of an existential void, but the result of that term’s incapacity to include the social relations that it provisionally stabilizes through a set of contingent exclusions.
This incompleteness will be the result of a specific set of social exclusions that return to haunt the claims of identity defined through negation; these exclusions need to be read and used in the reformulation and expansion of a democratizing reiteration of the term. That there can be no final or complete inclusivity is thus a function of the complexity and historicity of a social field that can never be summarized by any given description, and that, for democratic reasons, ought never to be (Buter 1993: 219-220).