The real difference in the two Constitutions must be sought in the amending power. To the amending of the unwritten portions of either there is no check on Parliament or on Congress, other than public {102} opinion. To the amending of the written portion of the British Constitution, there is likewise no check other than public opinion. Parliament amends the written and unwritten portions of the Constitution,--at the will of a majority of the House of Commons. Congress cannot so amend the written portions of the American Constitution; that is a prerogative of the voters alone. Therein lies the mystery of the alleged respective "flexity" and "rigidity" of the two. But the mystery is less, and the distinctions of flexity and rigidity grow of uncertain value when it is realized that both Constitutions are being constantly changed by the genius of our race. As in the case of our laws, our Constitutions are being steadily interpreted in accord with the will of the voters. That we do not change more suddenly is due to the conservative, yet discreet, action of our representatives, sanctioned by the voters. An enactment of Parliament at variance with the British Constitution changes that Constitution. An enactment of Congress at variance with the written portion of the American Constitution does not change the Constitution but remains at variance with it. To uphold the written Constitution in such a case and to insist on the priority of its terms over the acts performed by representatives acting under it, early became the self-imposed duty of the American courts. "But this, although, as we may well think, a sound conclusion, was not a necessary one; and it was long denied by able statesmen, judges, and lawyers."[102-1] This function of the courts was for years a unique feature of the United {103} States government. "The right to deal thus with their legislatures had already been asserted in the States, and once or twice it had really been exercised. Had the question related to a conflict, between that [federal written] Constitution and the enactment of a State, it would have been a simpler matter. These two questions, under European written constitutions, are regarded as different ones. It is almost necessary to the working of a federal system that the general government, and each of its departments, should be free to disregard acts of any departments of the local states which may be inconsistent with the federal constitution. And so in Switzerland and Germany the federal courts thus treat local enactments. But there is not under any written constitution in Europe a country where a court deals in this way with the acts of its coördinate legislature."[103-1]