The Corwin Amendment was a proposed amendment to the United States Constitution passed by the United States Congress on March 2, 1861. Ohio Representative Thomas Corwin offered the amendment during the closing days of the Second Session of the 36th Congress in the form of House (Joint) Resolution No. 80. The proposed amendment would have forbidden attempts to subsequently amend the Constitution to empower the Congress to "abolish or interfere" with the "domestic institutions" of the states, including "persons held to labor or service" (a reference to slavery). In particular, the Corwin Amendment was intended to prohibit the Congress from banning slavery in those states whose laws permitted it.
Offering the amendment was a last-ditch effort to avert the outbreak of the Civil War. Corwin's resolution emerged as the House of Representatives's version of an earlier, identical proposal in the Senate offered by Senator William H. Seward of New York. However, the newly formed Confederate States of America was totally committed to independence, and so it ignored the proposed Corwin Amendment.
This proposed amendment is technically still before the states for ratification, because it was submitted to the states without a time limit. Adoption of the Thirteenth Amendment, abolishing slavery, ended any realistic chance of its being adopted.