But may not this concentration of authority in the hands of an international body create a kind of super-state? In any case this danger is very remote at the present time; but it is no less necessary that at its inception conditions should be agreed upon which will safeguard it from such a tendency. This might be done in one of two ways. It might, for instance, be ordained that the machinery of the League should not be unitary, but that the commissions requisite for various purposes should be independently appointed by the contracting nations and derive their mandate directly from them; and in the event of overlapping, the commissions concerned might adjust the matter by joint session. The other alternative is that there should be a supreme international authority, but that it should be subject to a “Barrier Act.”[52] This would provide that the power and the enactments of the authority should be perpetually subject to the revision of the contracting parties; and it would be impossible for the international body to take any material step outside the limits of its mandate and consequently to extend its sphere of authority without the general consent of the nations concerned. Perhaps both these conditions are necessary—the direct appointment of commissions and the Barrier Act; and in any case a general agreement should be reached beforehand as to the limits and nature of the functions to be vested in the international body. It is plain, of course, that in any event the League must stand upon consent. It will be a voluntary association of free peoples; and its maintenance will depend upon the impossibility of its ever accruing any authority sufficient to prevent the withdrawal of any nation which might be so minded. It is questionable whether once the League had come into operation, any nation could afford to withdraw; but no power should be veiled in it to coerce a nation to remain in the League against its will. The basis of free and voluntary association is the only guarantee of genuine and fruitful solidarity. Footnote 52: The Barrier Act was a Presbyterian device against hasty innovation. “Every proposal which contemplates a material change in the constitution of the Church or in its laws respecting doctrine, discipline, government, or worship, after being considered and accepted by the Synod, must be sent down to Presbyteries for their approval or disapproval, before it can become the law of the Church.” (The Book of Order of the Presbyterian Church of England, p. 50.) Just so, the Federal Amendment to the Constitution of the United States relative to prohibition had to be referred to the several states for endorsement before final ratification.