imprisonment for debt

Can it be doubted but the legislatures of the States, so far as relates to their own process, have a right to abolish imprisonment for debt altogether, and that such law might extend to present, as well as future imprisonment?... Imprisonment of the debtor may be a punishment for not performing his contract, or may be allowed as a mean for inducing him to perform it. But a State may refuse to inflict this punishment, or may withhold it altogether, and leave the contract in full force. Imprisonment is no part of the contract, and simply to release the prisoner, does not impair its obligation.