The framers of the Constitution were not engaged in the same work of creating new political societies, but they were to provide for such surrenders by existing States of their present unquestioned legislative authority, as the dictates of sound policy and the evils of past experience seemed to require. When this subject was first brought forward in the Convention, the restriction was made to embrace all retrospective laws bearing upon contracts, which were supposed to be included in the term "_ex post facto_ laws." It being ascertained, however, that the latter phrase would not, in its usual acceptation, extend to civil cases, it became necessary to consider how such cases were to be provided for, and how far the prohibition should extend. The provision of the Ordinance was regarded as too sweeping; no legislature, it was said, ever did or can altogether avoid some retrospective action upon the civil relations of parties to existing contracts, and to require it would be extremely inconvenient. At length, a description was found, which embodied the extent to which the prohibition could with propriety be carried. The legislatures of the States were restrained from passing any "law impairing the obligation of contracts";--a provision that has been found amply sufficient, and attended with the most salutary consequences, under the interpretation that has been given to it.[305] Bills of attainder and _ex post facto_ laws, which had not been included in the prohibitions on the States by the committee of detail, were added by the Convention to the list of positive restrictions, which was thus completed.