This book examines the political, labor, and assimilation history of Mexican immigrants in metropolitan Chicago during the first half of the twentieth century. Beginning in the mid-1920s and extending into the years of the Great Depression, the New Deal, and the Cold War, Mexican immigrants engaged in a wide-range of political activism, and their political beliefs were shaped by the Mexican Revolution. Mexican immigrant political activists included men and women, middle-class businessmen and professionals, and blue-collar laborers from urban and rural backgrounds. Over time, Mexican immigrants formed distinct conservative, liberal, and radical transnational societies that competed with each other to mold the identities and influence the political beliefs of the broader Mexican, Mexican American, and Latino populations of Chicago and Northwest Indiana. Initially, Mexican conservatives, liberals, and radicals all defined themselves as patriots loyal to the Mexican state, but over the course of the 1920s and 1930s, profound political events in Mexico and in the United States led the conservatives to become the most critical of the Mexican state and the most amenable to U.S. naturalization. While the liberals and radicals tended to decline U.S. citizenship, conservative Mexican Catholics become U.S. citizens in great numbers, and they did so because they sought to protect themselves from both the anticlerical policies of Mexican government and from the deportation policies of the United States government.