 The onset of World War II increased economic unrest in Guatemala . Ubico responded by cracking down more fiercely on any form of protest or dissent . In 1944 , popular revolt broke out in neighboring El Salvador , which briefly toppled dictator Maximiliano Hernández Martínez . However , he quickly returned to power , leading to a flood of exiled El Salvadorian revolutionaries moving to Guatemala . This coincided with a series of protests at the university in Guatemala City . Ubico responded by suspending the constitution on 22 June 1944 . The protesters , who by this point included many middle @-@ class members in addition to students and workers , called for a general strike , and presented an ultimatum to Ubico the next day , demanding the reinstatement of the constitution . They also presented him a petition signed by 311 of the most prominent Guatemalan citizens . Ubico sent the police to disrupt the protests by firing on them , and declared martial law . Clashes between protesters and the military continued for a week , during which the revolt gained momentum . At the end of June , Ubico submitted his resignation to the National Assembly , leading to huge celebrations in the streets . 
