Why do historians disagree about when the Mexican Revolution ended?

Historians disagree on the end date of the Mexican Revolution because the conflict evolved from a clear political movement into a complex, long-term social and economic upheaval. While the violence of 1910 provides a definitive start, the conclusion is less distinct, leading scholars to propose several different milestones:1

• 1917: Some historians point to the adoption of the Constitution of 1917, which codified the aspirations of revolutionary groups and established a new legal framework for the country.21
• 1920: This is the most common convention used by scholars, marking the transition to the presidency of Álvaro Obregón and the beginning of efforts to stabilize the nation after years of civil war.314
• 1920s: Others argue that the revolution continued through the various political and military adjustments that occurred throughout the decade.1
• 1940: A final group of historians contends that the revolution did not truly conclude until 1940, when the movement's goals were fully institutionalized as guidelines for national policy.14

Ultimately, these differing perspectives reflect the transition from active, sporadic warfare to the gradual institutionalization of revolutionary reforms.14