"It is very certain that [the commerce clause] grew out of the abuse of the power by the importing States in taxing the non-importing, and was intended as a negative and preventive provision against injustice among the States themselves, rather than as a power to be used for the positive purposes of the General Government."

Next Quote

The management of foreign relations appears to be the most susceptible of abuse of all the trusts committed to a Government, because they can be concealed or disclosed, or disclosed in such parts and at such times as will best suit particular views; and because the body of the people are less capable of judging, and are more under the influence of prejudices, on that branch of their affairs, than of any other. Perhaps it is a universal truth that the loss of liberty at home is to be charged to provisions against danger, real or pretended, from abroad.

— James Madison