On June 1, 1812, President James Madison sent Congress a message asking for a declaration of war with Great Britain. The House adopted the war resolution on June 4 by a vote of 79-49, and it was then sent to the Senate for approval. The Senate made amendments to the House war resolution, and voted in favor of the changes on June 17, 19-13. On June 18 the House approved the amendments. President Madison signed the declaration of war on June 18.
Senate Amendments to the House Declaration of War, HR 12A-B3, 6/17/1812, Records of the U.S. House of Representatives
House Approval of the Senate Amendments to the House Declaration of War, HR 12A-B3, 6/18/1812, Records of the U.S. House of Representatives
Wars aren’t built in a day.