“You should come to a complete stop before proceeding through the intersection.”

That’s a traffic rule. We may not always follow it, but according to the law, we should follow it.

This is a legal norm —a specification of how we should or should not behave, according to the law.

How are we to understand the normative force of legal norms? Are they reducible to moral norms? Are they nothing more than expressions of social conventions? Do legal norms exist separately from moral norms?

This is an old question in the philosophy of law and political philosophy.

We don’t need to consider it further, other than to point out that legal claims may be a distinct category of normative claims.

It’s easy to find examples of policies that may be legally justified in a certain sense, but not morally justified. Think of laws prohibiting interracial marriage, or prohibiting women from voting.

Libertarian critics may regard taxation laws as normative in a legal sense (they agree that they should obey the law) but not morally justified, and will campaign to change those laws.

Examples like these make it clear that, on the face of it, there are differences between the normativity of legal claims and the normativity of moral claims.