So long and in so far as the Commonwealth does not exercise its jurisdiction, such jurisdiction remains with the States. This does not apply in cases where the Commonwealth possesses exclusive jurisdiction.
The National Cabinet may object to State laws relating to the subjects of [Article 7], Number 13, whenever the general welfare of the Commonwealth is affected thereby.
ARTICLE 13
The laws of the Commonwealth are supreme over the laws of the States which conflict with them.
If doubt arises, or difference of opinion, whether State legislation is in harmony with the law of the Commonwealth, the proper authorities of the Commonwealth or the central authorities of the States, in accordance with more specific provisions of a national law, may have recourse to the decision of a supreme judicial court of the Commonwealth.
ARTICLE 14
The laws of the Commonwealth will be executed by the State authorities, unless otherwise provided by national law.
ARTICLE 15
The National Cabinet supervises the conduct of affairs over which the Commonwealth has jurisdiction.