Prof. Roberta Bayer offers an excellent summary of James Wilson’s views on where democracy’s legitimacy comes from in a piece at the Library of Law and Liberty. Wilson believed that democracy was premised on a capacity to have a knowledge of justice. This knowledge of justice was found through reason and conscience, both of which were thought to be divine gifts. Because of the divine nature of this knowledge (i.e., natural law), it overrided any artificial law and, to Wilson, was the only legitimate defense of democracy.
Excerpts from the piece:
James Wilson, signer of the Declaration of Independence, important figure at the Constitutional Convention, and among the first justices of the US Supreme Court (1789-1798), argued more forcibly than any other Framer that philosophical skepticism is the enemy of self-government. Wilson argued that the philosophers John Locke (1632–1704) and David Hume (1711–1776) advanced theories that were antithetical to democratic government, because they deny to human nature the moral properties necessary to a knowledge of justice.
[F]irst, to impose laws without the people’s consent is “mere tyranny”; and second, people are fitted for self-government because they have a natural capacity to know the natural law.
[I]f people do not have the natural capacity to determine their own good and the good of others in a reasonable way, is it possible to defend democracy and the principle of consent?