The principle that statutory law, in order to be valid, must be in conformity with constitutional requirements, is a product of American jurisprudence, and peculiar to it. That the acts of the legislatures of subordinate political units must agree with the conditions and recognize the limits laid down by the superior sovereign power is of course not peculiar to the United States; but that the legislative acts of the highest legislative body itself are void if not warranted by the Constitution under which that body is organized, is nowhere else admitted, - neither in England, which is without a written Constitution, nor in any other Continental country which has one.