There is still another branch of their jurisdiction, of a grand and imposing character, which places them far above the celebrated Amphictyonic council. The Constitution of the United States has made them the arbiters between conflicting sovereigns. They decide whether the sovereign power of the States has been exercised in conformity with the Constitution and laws of the United States; and, if this has not been done, they declare the laws of the State Legislatures to be void. Their decisions thus control the exercise of sovereign power. No tribunal ever existed, possessing the same, or even similar authority. Now, Sir, suppose you bring these judges to Washington, and employ them in banc but six weeks or two months in the year, is it not certain that they will gradually become less and less fit to decide upon these different codes, and that they will at length nearly lose all recollection of the peculiar local laws of the different States? Every judicial duty which each of them would then be required to perform, would be to prepare and deliver a few opinions annually in banc. The judgment, like every other faculty of the mind, requires exercise to preserve its vigor. That judge who decides the most causes, is likely to decide them the best. He who is in the daily habit of applying general principles to the decision of cases, as they arise upon the circuits, is at the same time qualifying himself in the best manner for the duties of his station on the bench of the Supreme Court.