Final answer:
The 'Second American Revolution' mentioned by President James Madison refers to the War of 1812, a conflict that stemmed from unresolved issues between the United States and Great Britain and solidified American sovereignty and national pride.
Step-by-step explanation:
The conflict referred to as the "Second American Revolution" by President James Madison is the War of 1812. This war, often known as the Second War of American Independence, was driven by multiple causes including the British practice of impressment, where American sailors were taken at sea and forced to fight on British warships, and British support for Native Americans opposing U.S. expansion in the Great Lakes region. Despite setbacks such as the attempted invasion of Canada and the burning of Washington, D.C., the war ended with the Treaty of Ghent and was considered an American victory, leading to an increased sense of national identity and the eventual decline of the Federalist Party.