8. Maximilian was installed as the Emperor of Mexico
During the French intervention in Mexico in the mid-nineteenth century the United States was unable to enforce the principles of the Monroe Doctrine, occupied as it was with the American Civil War. Maximilian, brother of the Austrian Emperor Franz Joseph, was installed by French Emperor Napoleon III as Emperor of Mexico, supported with troops of the French Empire. The Mexican aristocracy largely opposed the Emperor, as did the revolutionaries led by Benito Juarez. When the American Civil War ended, US support of Juarez became more overt, and the departure of the French in 1866 led to the collapse of the Mexican Empire. Maximilian, lacking support among the Mexican people, was arrested, tried for treason, and executed by his former subjects, most of whom had never fully accepted him as the legitimate ruler of Mexico. His refusal to restore democracy to Mexico led to his demise, and he remains controversial in Mexico today.