20th century
By the 1920s, the emerging middle and working classes were powerful enough to elect a reformist president, whose program was frustrated by a conservative congress. Continuing political and economic instability resulted in a coup and quasi-dictatorial rule of General Carlos Ibáñez (1924-32).
When constitutional rule was restored in 1932, a strong middle-class party, the Radicals, emerged. It became the key force in coalition governments for the next 20 years. In the 1920s, Marxist groups with strong popular support developed. During the period of Radical Party dominance (1932-52), the state increased its role in the economy.
Another new force that emerged was the Nazi Party. The party was created on 1932, during the anarchy that succeeded the fall of Ibáñez's government. Months before the elections, Nazi leader González von Marées surpsingly criticized the policies of Hitler and the Third Reich. However, that same year, the Nazis led a revolt which ended on the supression of it and the arrest of various Nazi leaders.
The 1964 presidential election of Christian Democrat Eduardo Frei Montalva by an absolute majority initiated a period of major reform. Under the slogan "Revolution in Liberty," the Frei administration embarked on far-reaching social and economic programs, particularly in education, housing, and agrarian reform, including rural unionization of agricultural workers. By 1967, however, Frei encountered increasing opposition from leftists, who charged that his reforms were inadequate, and from conservatives, who found them excessive.