this is why iris young draws on and expands Habermas work. She argues that his notion of justice remains distributive. I don't think she makes an adequate argument.
Habermas wants to address the way we institutionalize norms which then become part of our background assumptions which rarely get questioned. As opposed to Rawls, who elaborates an individualist, distributive account of justice, Habermas is interested in a collectivist, consensus account of justice. This translates into recognition that different groups have different needs and that they might require _equity_ rather than _equal treatment_ (substantive justice, rather than procedural justice).
But I repeat, he's not interested in creating debate clubs for the sake of debate clubs. He's interesting in institutionalizing a "public sphere". Institutions are about social practices (and they're normative. always. they can be nothing else. there is no such thing as a human society that doesn't have norms.) Unions, the civil rights struggle, the abolition movement, etc. any struggle we on the left consider emancipatory has been successful, in part, because there were institutionalized practices of communicative action that it could build on and expand and make _more_ emancipatory when possible.
Rawls is in search of the conditions under which ideal moral contracts might be drawn.
Habermas is more interested in the _foundations_ of rationality [1] in the minimal _conditions_ that even bring people to attempt to communicate with one another in the first place.
rationality is not in the conditions. rationality is not in communication. rather, the _foundations_ of rationality are located in the human propensity to communicate with one another as part of our nature as fundamentally social beings who live and love and work together to create their collective lives. we have to do this or we die, unlike many other animals.
in our collective lives, we try to communicate using symbolic systems, not just a narrow 'language', and this is because we want to be understood and others want to understand us.
understanding here is in the broader sense that Gadamer uses it. I understand or try to understand what it might be like to be disabled. This isn't about me communicating with you, Marta, and misinterpreting words, etc., although i can use those micro-examples as illustrations to wind my way to H's larger point. It's about me trying to take into account where you are coming from and you doing the same. Just as an example., not an attack. No namby pamby I feel your pain, but hard, messy, achingly difficult, sometimes humiliating _understanding_.
[1] rationality here is not to be confused with a narrow notion of ratiopnality as technical, calculating rationality, but what some used to call REASON as opposed to rationality. Aristotle's phronesis, rather than techne.