Republican Party (United States) newspaper magnate Kay Thorndyke (Angela Lansbury) intends to make her lover, aircraft tycoon Grant Matthews (Spencer Tracy), President of the United States with her as the power behind the throne. Thorndyke plans to use her newspaper chain's influence to brokered convention the 1948 Republican National Convention, so it will choose Matthews as a compromise dark horse candidate instead of Thomas E. Dewey, Robert A. Taft, or former Governor of Minnesota, Harold Stassen.