OTTAWA — The federal government’s appeal of a ruling that expanded First Nations children’s rights to public services is “a slap in the face,” says the Assembly of First Nations. The November ruling by the Canadian Human Rights Tribunal widened the applicability of Jordan’s Principle, a rule that says that when governments disagree about who’s responsible for providing services to First Nations children, they must help a child in need first and argue over the bills later. In November, the tribunal ruled that the principle applies to children who live off reserves if they identify as members of a particular First Nation and that nation claims them — even if they don’t have status under the Indian Act — and to children of parents who could legally get status but do not have it.