First. To all cases in law and equity, arising under the Constitution and the laws of the United States . This corresponds with the two first classes of causes, which have been enumerated, as proper for the jurisdiction of the United States. It has been asked, what is meant by “cases arising under the Constitution,” in contradiction from those “arising under the laws of the United States”? The difference has been already explained. All the restrictions upon the authority of the state legislatures furnish examples of it. They are not, for instance, to emit paper money; but the interdiction results from the Constitution, and will have no connection with any law of the United States. Should paper money, notwithstanding, be emited, the controversies concerning it would be cases arising under the Constitution and not the laws of the United States, in the ordinary signification of the terms. This may serve as a sample of the whole.
It has also been asked, what need of the word “equity”? What equitable causes can grow out of the Constitution and laws of the United States? There is hardly a subject of litigation between individuals, which may not involve those ingredients of fraud