Custom makes us insensible to folly, and even to injustice. Thus the tax on letters has gained an undeserved immunity, which is augmented by a prevailing notion, sometimes supposed to find authority even in the Constitution, that the Post-Office must support itself. Whether regarded as rule or maxim or provision of the Constitution, it is without foundation, and sooner or later will be classed with those “vulgar errors” which are as disturbing in government as in science. There is nothing in the Constitution or in reason to distinguish the Post-Office in this respect from the Army, the Navy, or the Judiciary. The Constitution confers upon Congress the power “to establish post-offices and post-roads,” precisely as it confers upon Congress the power “to raise and support armies,” the power “to provide and maintain a navy,” and the power “to constitute tribunals inferior to the Supreme Court”; and in each of these cases it is empowered “to make all laws which shall be necessary and proper for carrying into execution the foregoing powers.” Nobody suggests that now in peace our armies shall amplify their commissariat by enforced contributions, that our navy shall redouble its economies by supplementary piracy, or that our tribunals inferior to the Supreme Court shall eke out a salary by requisitions on the suitors, to the end that each of these departments may be in some measure “self-supporting.” Why, then, should the Post-Office be subjected to a different rule? Not, surely, because it is less beneficent; not because it is the youngest child of Government, a very Benjamin, coming into being long after the others. But such is the case. The rule for the others is discarded when we come to the Post-Office, and here for the first time we hear that a Department of Government must be “self-supporting.”