Mexican Civil War (Southern Victory)
Date 1917 to c. 1925
Location Mexico
Result Continuation of the Hapsburg Empire
Mexican Popular Revolutionaries with the support of the United States Mexican Monarchists with the unofficial support of the Confederate States
Commanders and leaders
Emperor Maximilian III

The Mexican Civil War followed a revolt against Maximilian III, the Hapsburg Emperor 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 alongside the Hapsburg loyalists, known as the Mexican Monarchists.

Surprisingly, the Monarchists 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. The royalist barrels crushed the rebels at the defining Battle of San Luis Potosi.

The incident reinforced the already-strong association of Mexico with the Confederate States and the rest of the Entente, and especially with Freedom Party chairman Jake Featherston when he eventually became President of the Confederate States.