question
are repugnant to the tenth section of the first article of the
Constitution of the United States. The material words of that section
are: "No State shall pass any bill of attainder, _ex post facto_ law, or
law impairing the obligation of contacts."

The object of these most important provisions in the national
constitution has often been discussed, both here and elsewhere. It is
exhibited with great clearness and force by one of the distinguished
persons who framed that instrument. "Bills of attainder, _ex post facto_
laws, and laws impairing the obligation of contracts, are contrary to
the first principles of the social compact, and to every principle of
sound legislation. The two former are expressly prohibited by the
declarations prefixed to some of the State constitutions, and all of
them are prohibited by the spirit and scope of these fundamental
charters. Our own experience has taught us, nevertheless, that
additional fences against these dangers ought not to be omitted. Very
properly, therefore, have the convention added this constitutional
bulwark, in favor of personal security and private rights; and I am much
deceived, if they have not, in so doing, as faithfully consulted the
genuine sentiments as the undoubted interests of their constituents. The
sober people of America are weary of the fluctuating policy which has
directed the public councils. They have seen with regret, and with
indignation, that sudden changes, and legislative interferences in cases
affecting personal rights, become jobs in the hands of enterprising and
influential speculators, and snares to the more industrious and less
informed part of the community. They have seen, too, that one
legislative interference is but the link of a long chain of repetitions;
every subsequent interference being naturally produced by the effects of
the preceding."[50]

It has already been decided in this court, that a _grant_ is a contract,
within the meaning of this provision; and that a grant by a State is
also a contract, as much as the grant of an individual. In the case of
_Fletcher v. Peck_[51] this court says: "A contract is a compact between
two or more parties, and is either executory or executed. An executory
contract is one in which a party binds himself to do, or not to do, a
particular thing; such was the law under which the conveyance was made
by the government. A contract executed is one in which the object of
contract is performed; an