Final answer:
Woodrow Wilson stated that the question of the relation of the states to the federal government is the cardinal question of our constitutional systems.
Step-by-step explanation:
The U.S. president who stated, "The question of the relation of the states to the federal government is the cardinal question of our constitutional systems" is Woodrow Wilson. Wilson believed that the balance of power and relationship between the states and the federal government was crucial to the functioning of the constitutional system. He emphasized the importance of states' rights and the limitations of federal authority.