economic boom also swelled the ranks of the middle classes. Since the political system excluded their interests as well, the middle class helped build reformist political parties that forged links to labor. Such was the case of the populist Democratic party and the Radical party. The Democratic party, founded in 1887, appealed to the lower middle class and labor. This populist political party supported labor reform, public education, tariff barriers to stimulate industrialization, more taxes on land and business, and direct election of the president. More middle-of-the road reformist parties, such as the anti-clerical Radical party (founded in 1863), also expanded. Both parties had congressional representation.
After World War I, the Democratic and Radical parties seriously challenged the parties of the oligarchy: the Conservative and Liberal parties. Chile fell into a deep economic depression during the worldwide economic slump that followed the end of the Great War. The precipitous fall of nitrate prices due to the invention of synthetic nitrates during the war aggravated matters. Labor and the middle class clamored for government action to ease the hardship caused by the Depression. Socialists, communists, and anarcho-syndicalists made significant in-roads in the labor movement. Their militancy threatened social and political stability.
The Conservative government remained inflexible in its defense of economic liberalism and violent labor repression. This stance encouraged another enduring feature of Chilean politics: electoral coalitions. A minority sector of the Liberal party allied with the Radical and Democratic parties to form the Liberal Alliance. This was Chile's first populist electoral coalition, one that brought together the middle class, significant sectors of labor, and a breakaway segment of the upper class.. Their leading light, young firebrand Arturo Alessandri of the Liberal party, became president in 1920 on a platform of educational, labor, and economic reform. The Liberal Alliance defeated the National Union, a coalition formed by the Conservative party and most of the Liberal party.
Although his government also violently repressed the more militant factions of labor, it did propose paternalistic labor code and social welfare reforms. However, oligarchs used the congress, especially their control of the powerful senate, to block his efforts. Conservative obstructionism and the ensuing economic disorder, high inflation, and social unrest caused Alessandri to resign his presidency in 1924.
The ungovernability of Chile prompted the demise of the parliamentary republic and ushered in the return of presidential dominance with the constitution of 1925. Political stability, however, eluded Chile until 1932. Between 1924 and 1925 a military junta established paternalistic labor code reforms that gave government control over unions and introduced social welfare modeled after the German program established by Otto von Bismarck in the 1880s. However, disgruntled military officers overthrew the junta in early 1925. This second military government supported organized labor even more, frequently intervening on its behalf in labor disputes. To further court urban labor, the junta asked Alessandri to take over the presidency in March