In December 1931, El Salvador's civilian president, Arturo Araujo, was overthrown in a military coup. Such an event was hardly unique in Salvadoran history, but the 1931 coup proved to be a watershed. Araujo had been the nation's first democratically elected president, and although no one could have foreseen the result, the coup led to five decades of uninterrupted military rule, the longest run in modern Latin American history. Furthermore, six...