Federales in the context of "Better Call Saul"

The Federal Army (Spanish: Ejército Federal), also known as the Federales (English: Federals) in popular culture, was the army of Mexico from 1876 to 1914 during the Porfiriato, the rule of President Porfirio Díaz, and during the presidencies of Francisco I. Madero and Victoriano Huerta. Under President Díaz, a military hero against the French Intervention in Mexico, the senior officers of the Federal Army had served in long-ago conflicts; at the time of the outbreak of the Mexican Revolution, most were old men, incapable of leading troops on the battlefield. When the rebellions broke out against Díaz following fraudulent elections in 1910, the Federal Army was incapable of responding.

Although revolutionary fighters helped bring Francisco I. Madero to power, Madero retained the Federal Army rather than the revolutionaries. Madero used the Federal Army to suppress rebellions against his government by Pascual Orozco and Emiliano Zapata. Madero placed General Victoriano Huerta as interim commander of the military during the Ten Tragic Days of February 1913 to defend his government. Huerta changed sides and ousted Madero's government. Rebellions broke out against Huerta's regime. When revolutionary armies succeeded in ousting Huerta in July 1914, the Federal Army ceased to exist as an entity, with the signing of the Teoloyucan Treaties.

The Mexican Border War, also known as the Border Campaign, refers to a series of military engagements which took place between the United States military and several Mexican factions in the Mexican–American border region of North America during the Mexican Revolution.

From the beginning of the Mexican Revolution in 1910, the United States Army was stationed in force along the border and, on several occasions, fought with Mexican rebels or regular federal troops. The height of the conflict came in 1916 when revolutionary Pancho Villa attacked the American border town of Columbus, New Mexico. In response, the United States Army, under the direction of General John J. Pershing, launched a punitive expedition into northern Mexico, to find and capture Villa. Although Villa was not captured, the US Army found and engaged the Villista rebels, killing Villa's two top lieutenants. The revolutionary himself escaped, and the American army returned to the United States in January 1917.