Cornwell Jr, Elmer E. "Bosses, machines, and ethnic groups." The Annals of the American Academy of Political and Social Science 353, no. 1 (1964): 27-39.
The boss and his urban machine, though products of many factors, were virtually unthinkable without their immi grant clienteles. These gave the machine its essential mass base. And the machine operated, in effect, as virtually the only agency facilitating the political—and economic—integration of the immigrants into the American community. This was done by soliciting—or "buying"—their votes with the familiar array of machine "services," bringing their representatives into the organization, offering a career ladder to some individuals, and giving general recognition to them as a group. Then the im migration flow virtually stopped during the 1920's. This, plus various urban reforms, the development of government- sponsored welfare services, and the like ended the era of the boss. Actually, two kinds of "immigration" have gone on since the twenties. The Negro has come in increasing numbers from the rural South to northern urban centers, and the Puerto Rican has sought wider opportunity in New York City. Though the present-day urban party has far less motive and ability to deal with these newcomers in the former manner, evidence suggests that they are finding their way into the party organizations and, hence, are to some extent being represented by them.