Final answer:
Due to internal strife, revolutionary factions, and fear of US invasions following incidents like the Veracruz clash, the Mexican government was likely unable or unwilling to mobilize large numbers of peasants for war.
Step-by-step explanation:
The Mexican government was reluctant to mobilize a large peasant army during the Mexican American War for multiple reasons. History tells us that internal strife and revolutions such as the one led by Francisco Madero against Porfirio Díaz, had fractured the country. The upheaval began in 1910 and by 1917, Mexico was entrenched in a violent conflict with numerous revolutionary factions. With the population divided, the Mexican government might not have been able to effectively raise a large peasant army even if it wanted to.
Moreover, historical events such as the Veracruz incident in 1914 and US military interventions increased tensions and contributed to public mistrust and fear of potential further invasions. Such factors likely influenced the Mexican government's unwillingness or inability to raise a large peasant force.