Ethics in linguistic space and the challenge of morality

For Kant and his followers, pure reason can be practical, and its substantive practical command is, broadly speaking, that we treat ourselves and others as worthy of respect as free and equal. If those who have defended the Kantian morality system are correct, this moral imperative will not be authoritative and inescapable simply because we don't know how to coherently reweave our practical commitments so as to leave it out, but because it is presupposed by the possibility of practical reason. On this model, the rational authority of moral dictates would be understood as absolute and universal.
But what if Kant and his followers have been wrong? What if the search for practical unconditionality turned out to be vain? Kant himself would most likely react to this news by pronouncing that, without a priori necessity, there could be no moral necessity, and without moral necessity, there could be no purity of motive, and without purity of motive, there could be no moral worth, and without moral worth, there could be no legitimate ascriptions of praise and blame. In short, for Kant and his orthodox followers, without unconditionality, the morality system would collapse.
I will argue that the search for a priori necessity behind moral law is indeed hopeless, but that this does not entail the collapse of the morality system. It does however force us to conceive a new way of accounting for practical normativity in the absence of unconditionality. It also requires that, in order to preserve morality, we find a defensible place for it as a contingent subset of ethics broadly construed. My answer is to provide a new account of morality, and practical normativity in general, against the backdrop of neopragmatism. My hope is to provide an alternative story which preserves the Kantian insight that practical necessity is driven by rational authority, but which does not presuppose unconditionality to explain the latter's force and inescapability. In short I will attempt to show that ethical principles, when considered in linguistic space, need not be a priori necessary to bind individuals in a genuinely authoritative sense.