Page:Joseph Story, Commentaries on the Constitution of the United States (1st ed, 1833, vol III).djvu/251

 CH. XXXIV.] of express contracts, if those, which are implied, might be impaired by state legislation. The constitution is not chargeable with such folly, or inconsistency. Every grant in its own nature amounts to an extinguishment of the right of the grantor, and implies a contract not to re-assert it. A party is, therefore, always estopped by his own grant. How absurd would it be to provide, that an express covenant by him, as a muniment attendant upon the estate, should bind him for ever, because executory, and resting in action; and yet, that he might re-assert his title to the estate, and dispossess his grantee, because there was only an implied covenant not to re-assert it.

§ 1372. In the next place, what is the obligation of a contract? It would seem difficult to substitute words more intelligible, or less liable to misconstruction, than these. And yet they have given rise to much acute disquisition, as to their real meaning in the constitution. It has been said, that right and obligation are correlative terms. Whatever I, by my contract, give another a right to require of me, I, by that act, lay myself under an obligation to yield or bestow. The obligation of every contract, then, will consist of that right, or power over my will or actions, which I, by my contract, confer on another. And that right and power will be found to be measured, neither by moral law alone, nor by universal law alone, nor by the laws of society alone; but by a combination of the three; an operation, in which the moral law is explained, and applied by the law of nature, and both modified and adapted to the exigencies of society by positive law. In an advanced