Why did Che Guevara believe guerrilla forces could defeat a regular army?

Che Guevara’s belief that guerrilla forces could defeat a regular army was a central tenet of his foco theory (foquismo), which he detailed in his influential manual, Guerrilla Warfare (1960).

His doctrine was predicated on three core principles:

• Capability: He maintained that guerrilla forces are inherently capable of defeating a conventional army.1
• Revolutionary Creation: He argued that it is not necessary to wait for all revolutionary conditions to exist before starting an uprising, as the act of rebellion itself can create the necessary conditions for success.1
• Strategic Environment: He believed that the rural landscapes of underdeveloped Latin American nations were uniquely suited for armed combat, providing the ideal terrain for guerrilla operations.1

This strategy relied on the understanding that guerrilla warfare is a political-military endeavor. By operating in concert with the people—who provide sanctuary, supplies, and information—guerrillas can harass a conventional force, erode its will to fight, and build sufficient strength to eventually overcome it.21