At best the principles that economists have supposed the choices of rational individuals to satisfy can be presented as guidelines for us to consider when we make our decisions.

Justice is happiness according to virtue.

Different political views, even if they're all liberal, in the sense of supporting liberal constitutional democracy, undoubtedly have some notion of the common good in the form of the means provided to assure that people can make use of their liberties, and the like.

No one deserves his greater natural capacity nor merits a more favorable starting place in society.

How did Madison get separation through Virginia and later Congress? The Baptists, the Presbyterians, and the smaller sects hated Jefferson; to them he was a secularist of the worst kind. But Madison could get Jefferson's bill passed because the Baptists, the Presbyterians, and smaller sects who were excluded in New England and in the South got together for their own protection.

Thus I assume that to each according to his threat advantage is not a conception of justice.

A political conception covers the right to vote, the political virtues, and the good of political life, but it doesn't intend to cover anything else.