on in value, and might
subject those who should be compelled to receive it to great
inconvenience and loss. But although no person is obliged to take in
payment any thing but coin, bank bills are by common consent taken in
the course of business and in payment of debts, because they may be
converted into specie by presenting them at the bank by which they are
issued.

Sec.6. Nor may a state "pass any bill of attainder, ex post facto law, or
law impairing the obligation of contracts." Bills of attainder and ex
post laws have been defined and considered. (Chap. XXXVII, Sec.5.) If these
laws are in their nature wrong, the states as well as congress should be
prohibited from passing them. Not less unjust are laws impairing the
obligation of contracts. Laws that should weaken the force of contracts,
or that would release men from their obligations, would be contrary to
the principles of justice, and destroy all security to the rights of
property.

Sec.7. As bankrupt laws release debtors from the payment of their debts,
and consequently impair the obligation of contracts, the question has
arisen whether the states have power to pass insolvent or bankrupt laws.
From decisions of the supreme court of the United States, which is the
highest judicial authority, it appears, that a state may not pass a
bankrupt law discharging a debtor from the obligation of a contract made
before such law was passed. But it was not to be considered a law
impairing the obligation of a contract, if it existed before the
contract was made; because the parties, who are presumed to know that
such law exists, may guard themselves against loss.

Sec.8. The last thing prohibited in this clause, is, "to grant any title of
nobility." This is forbidden to the states for the same reason as it is
prohibited to congress. (Chap. XXXVII, Sec.11.)

Sec.9. The first prohibition to the states in the next clause is to "lay
any imposts or duties on imports or exports, except what may be
absolutely necessary for executing their inspection laws." The
objections to the power of the states to lay duties have been
considered. They are founded upon the same reasons as have been given
for intrusting congress with this power; one of which is to secure
uniformity throughout the United States. (Chap. XXXII, Sec.6.) And as
congress is properly prohibited from laying duties on exports, (Chap.
XXXVI, Sec.8, 9,) there can be no good reason for allowing it to be done
by the sta