The assassination of Jose Calvo Sotelo in July 1936 gave general Emilio Mola, the military commander of Pamplona in northern Spain, the pretext to launch his coup.
Sotelo was a reprisal for the murder of Jose Castillo, a prominent l/w member of the Assault Guard.
His colleagues in the Assault Guard retaliated by targeting r/w figures. Their initial target was Gil Robles, but they were unable to locate him. Instead, they arrested and killed Sotelo.
Sotelo's assassination had a variety of consequences, which led to the outbreak of civil war.
Although the government was not directly involved in the murder, Gil Robles accused the government of ordering the assassination.
The murder also convinced many of the m/c that the government should end. For many in the m/c Sotelo's murder was evidence that the government had either begun murdering its own citizens or had lost control of the country.
Mola used these assassinations to begin his coup, claiming that the assassination was the first step of a communist plot to overthrow the government. Mola's claim was widely believed - leading figures on the left had been talking about revolution for some time.
The murder convinced Franco to take part in the coup against the government.
Military preparations for the coup had been going on in secret for months.
Until Sotelo's assassination Franco was unsure whether he should join the plotters. Sotelo's assassination persuaded Franco to join the military rebels.
Franco concluded that the republic was planning to kill leading figures on the right and therefore he joined the movement to overthrow the government.