"As for Habermas, he has always marked an epistemic break between secular reason and religious thought, with the advantage on the side of the first. Secular reason suffices to arrive at the normative conclusions we need, such as establishing the legitimacy of the democratic state, and defining our political ethic. Recently, his position on religious discourse has considerably evolved; to the point of recognizing that its “Potential macht die religiöse Rede bei entsprechenden politischen Fragen zu einem ernsthaften Kandidaten für mögliche Wahrheitsgehalte.” But the basic epistemic distinction still holds for him. Thus when it comes to the official language of the state, religious references have to be expunged. “Im Parlament muss beispielsweise die Geschäftsordnung den Presidenten ermächtigen, religiöse Stellungnahmen und Rechtfertigungen aus dem Protokoll zu streichen.”
I think that these positions of Rawls and Habermas show that they have not yet understood the normative basis for the contemporary secular state. I believe that they are on to something, in that there are zones of a secular state in which the language used has to be neutral. But these do not include citizen deliberation, as Rawls at first thought, or even deliberation in the legislature, as Habermas seems to think from the above quote. This zone can be described as the official language of the state: the language in which legislation, administrative decrees and court judgments must be couched. It is self-evident that a law before Parliament couldn’t contain a justifying clause of the type: “Whereas the Bible tells us that p.” And the same goes mutatis mutandis for the justification of a judicial decision in the court’s verdict. But this has nothing to do with the specific nature of religious language. It would be equally improper to have a legislative clause: “Whereas Marx has shown that religion is the opium of the people,” or “Whereas Kant has shown that the only thing good without qualification is a good will.” The grounds for both these kinds of exclusions is the neutrality of the state."