Why did the end of reciprocity end in 1865?

The end of reciprocity in 1865 can be attributed to significant political and economic shifts following the American Civil War. The war altered relationships between the United States and other nations, leading to a focus on national self-sufficiency and protectionist policies. Additionally, the economic challenges of post-war reconstruction prompted a re-evaluation of trade agreements, resulting in the abandonment of many reciprocal trade arrangements that had previously existed. As a result, the period marked a transition towards a more isolationist and protectionist approach in U.S. trade policy.