How does Tommie Shelby argue that Rawl’s original position, in which the parties are behind a veil of ignorance, “rules out a selection of a range of principles that would entail, encourage, or exacerbate racial injustice”?

Tommie Shelby’s “Race and Social Justice: Rawlsian Considerations”
How does Tommie Shelby argue that Rawl’s original position, in which the parties are behind a veil of ignorance, “rules out a selection of a range of principles that would entail, encourage, or exacerbate racial injustice”?
“Race, Personhood, and Equal Citizenship,” Shelby considers Charles Mills’ objection that any liberal contractarian approach (like Rawls’ approach) extends equal moral status to whites only.

How does Shelby respond to this objection? In your explanation, specifically focus on (a) Rawls’ claims in A Theory of Justice and then (b) his claims in Political Liberalism.

Do you think Shelby is correct in arguing against Shiffrin’s position regarding the need for an anti discrimination provision in the two principles and that a “fair equality of opportunity for all citizens regardless of race would remove many of the socioeconomic burdens that racial minorities presently shoulder because of the history of racial injustice”?