Section 2. Jurisdiction is ceded to the United States over the military reservations of Fort Abraham Lincoln, Fort Buford, Fort Pembina, and Fort Totten, heretofore declared by the president of the United States; provided, legal process, civil and criminal, of this state, extends over those reservations in all cases in which exclusive jurisdiction is not vested in the United States, or of crimes not committed within the limits of those reservations. The legislative assembly may provide, upon the terms and conditions it adopts, for the acceptance of any jurisdiction as may be delegated to the state by act of Congress.