Accordingly, when Congress appeared to overstep the limits which the Constitution set to its authority, the states naturally looked for some means of making the checks imposed upon the general government effective. True, the Constitution itself did not specify how this was to be done; but neither could one find in it any provision for enforcing the limitations on the authority of the states. The general government, however, had supplied itself with the means of self-protection by calling into existence the veto power of the Federal judiciary. This made the checks upon the authority of the states operative. But how were those imposed by the Constitution on the general government itself to be enforced? Not by the Federal government or any of its organs, since this would allow it to interpret the Constitution to suit itself. If the general government should have the right to interpret and enforce the constitutional limitations on the powers of the states, it would for a like reason follow that the states should interpret and enforce the constitutional limitations on the authority of the general government itself. To carry out in good faith what appeared to be the purpose of the Constitution, _i.e._, to limit the authority of the general government as well as that of the states, it would seem to be necessary to make each the judge of the other's powers. It would devolve then on the state governments to keep the general government within the bounds which the Constitution set to its authority. This could be accomplished, however, in no other way than by a veto on such acts of the general government as, in the opinion of the state, exceeded its constitutional authority. Those who believed in a federal as opposed to a national government and who therefore wished to enforce the constitutional checks on the general government, were irresistibly impelled toward the doctrine of nullification as the sole means of protecting the rights of the states. As Von Holst says, "Calhoun and his disciples were not the authors of the doctrine of nullification and secession. That question is as old as the Constitution itself, and has always been a living one, even when it has not been one of life and death. Its roots lay in the actual circumstances of the time, and the Constitution was the living expression of these actual circumstances."[134] Madison, in _The Federalist_, refers in a vague and indefinite manner to the power of a state to oppose an unjustifiable act of the Federal government.