"The States are every day giving proofs that separate regulations are more likely to set them by the ears than to attain the common object. When Massachusetts set on foot a retaliation of the policy of Great Britain, Connecticut declared her ports free. New Jersey served New York in the same way. And Delaware I am told has lately followed the example in opposition to the commercial plans of Pennsylvania. A miscarriage of this attempt to unite the states in some effectual plan will have another effect of a serious nature….I almost despair of success." —James Madison in a letter to Thomas Jefferson, 1786

To which problem is James Madison referring in his letter to Thomas Jefferson?
A.
the inability of Congress to regulate commerce under the Articles of Confederation
B.
the lack of a judiciary branch to mediate disputes between two or more states
C.
the power of the executive branch to undermine congressional authority over commerce
D.
the supremacy of the central government over the states under the Articles of Confederation