The Federalist Party lost support after the war of 1812 because it was opposed to the ideals of a democracy as well as supporting peace with Britain and war with France. The Democratic-Republican party supported war with Britain and peace with France. The final nail in the coffin for the Federalist Party was the British behaviour towards the American citizens during the war with France. This caused anti-British sentiment and as a result, people stopped supporting the Federalist Party.