Bret Baier chronicles the untold story of America’s political parties, revealing how they were despised by the Founders, molded by titans like Jackson, Lincoln, Roosevelt and Reagan, and transformed by outsiders in times of crisis. This sweeping and surprising five-part documentary - the latest in Baier's 'unauthorized history' series - begins with the drafting of the Constitution and concludes with the unprecedented political developments of the tumultuous 2024 Trump v. Harris campaign.