The Mexican Civil War followed a revolt against Maximilian III, the HapsburgEmperor of Mexico in the 1920s. The anti-Hapsburg rebels, known as the "Popular Revolutionaries", were tepidly supported by the United States. The Confederate States, fresh off their defeat in the Great War, did not officially support their traditional Hapsburg allies, but many members of the Freedom Party (including Jefferson Pinkard) traveled to Mexico as private citizens to fight for the Hapsburgs. Surprisingly, they were able to defeat the rebels despite U.S. support, suggesting that U.S. military hegemony in North America was beginning to wane. This conflict was also an opportunity for Confederate royalist volunteers to freely develop and improve barrels, since the United States, victorious in the Great War, had outlawed barrels in the Confederate States.