1930s: Spain experiences several major transitions in government. The dictatorship of Primo de Rivera, begun in 1923, is ended in 1930. The Second Republic lasts from 1931 to 1936. The Spanish Civil War begins in 1936. With the end of the Civil War in 1939, Francisco Franco rises to power as dictator of Spain.

Today: Spain is a constitutional monarchy. King Juan Carlos I serves as head of state. Based on a constitution ratified in 1978, the prime minister oversees a parliament (known as the Cortes Generales), which includes a Congress of Deputies and a Senate. Members of parliament are elected primarily by popular vote via universal suffrage.

1930s: With the outbreak of World War II in 1939, Spain retains a stance of official neutrality. However, Spain secretly supports the Axis forces of Germany, Italy, and Japan during most of the war. Toward the end of World War II, Spain switches unofficial...