Based on history and the play by Franz Werfel from Bertita Harding's novel, elected Mexican President Juarez overcomes the imposition of Maximilian.
In 1863 Empress Eugenie (Gale Sondergaard) advises Emperor Napoleon III (Claude Rains) to give Mexico Maximilian von Hapsburg (Brian Aherne) as a monarch. French soldiers hold a plebiscite, and a peasant shouting "Juarez" is shot. General Porfirio Diaz (John Garfield) gives President Benito Juarez (Paul Muni) a proclamation to sign. Marechal Bazaine (Donald Crisp) says that Maximilian got 99% and welcomes him and his wife Carlota (Bette Davis). Col. Lopez (Gilbert Roland) says that a plague kept people away. Maximilian finds a letter from Juarez warning him of the fraud. Juarez rejects assassination. Vice President Alejandro Uradi (Joseph Calleaia) asks Juarez to step aside because he is an Indian. Carlota prays to Mary for a son; but Maximilian and Dr. Samuel Basch (Harry Davenport) know she can't bear children. Maximilian learns that Juarez has armies and wants to negotiate; but Bazaine launches an offensive. Juarez, supported by President Lincoln, disbands the army and retreats north while Diaz attacks valiantly and is captured. Maximilian appoints Miramon (Henry O'Neill) minister of war and Tomas Mejia (Billy Wilderson) commander-in-chief even though he is Aztec. When Maximilian refuses to give the land of the peons back to 85 men, conservative politicians resign.
Juarez mourns the death of Lincoln but sends rifles to peasants for guerrilla warfare. Maximilian refuses to sign Bazaine's repressive decree and learns his election was a fraud. Maximilian tells Carlota he must abdicate, but she persuades him to protect the people. Maximilian asks Diaz for help to bring peace. Diaz tells him of Juarez's goals, and Maximilian says a king can rule best. Maximilian sends Diaz to Juarez to make him prime minister. Maximilian tells Carlota they should adopt a successor. Diaz tells Juarez that Maximilian offers him his program except the word "democracy;" but Juarez notes its importance. Maximilian proclaims little Augustin (Mickey Kuhn) crown prince. When Juaristas attack, Maximilian signs the decree to execute everyone found with a gun. Wounded Pepe (Manuel Diaz) shows Juarez the decree and dies. The U. S. ambassador warns Napoleon III to pull the French out of Mexico.
Uradi tells Juarez that his term has expired, and Diaz threatens Uradi; but Juarez calms Diaz. Lopez tells Maximilian that Uradi has the U. S. arms; but Bazaine informs Maximilian that the French are withdrawing. Carlota says she will go to Napoleon. Juarez goes alone to Uradi, but soldiers refuse to shoot him. Uradi bars the door, and Juarez speaks to the people. Uradi comes out, orders Juarez arrested, but is shot. Carlota breaks in on Napoleon III with the Treaty of Miramar, castigates him, and collapses. Carlota fears Napoleon will poison her and becomes paranoid. Bazaine advises Maximilian to abdicate, and Maximilian gets a letter from Prince Metternich that his wife is mentally ill. Maximilian abdicates; but Lopez pleads, and Maximilian decides to stay. Later Lopez betrays the city to save lives, and Maximilian, Miramon, and Mejia are captured. Juarez has these three executed and asks forgiveness.
This drama is fairly accurate (except for Uradi's attempted
coup; also in fact Diaz escaped) and shows how a great native
American (Juarez) made Mexico a democratic nation under a constitution
despite imperialistic intervention by France and Maximilian.