Would make the states' "domestic institutions" (i.e. slavery) impervious to the constitutional amendment procedures established in Article V and immune to abolition or interference from Congress. Proposed March 2, 1861, and still before the states. Pending since March 2, 1861. Latest ratification took place on June 2, 1863. The Corwin Amendment is a proposed amendment to the United States Constitution that has never been adopted but, owing to the absence of a ratification deadline, could theoretically still be adopted by the state legislatures. It would have shielded slavery within the states from the federal constitutional amendment process and from abolition or interference by Congress. Wiki link