 As part of his efforts to limit unemployment, Hoover sought to cut immigration to the United States, and in 1930 he promulgated an executive order requiring individuals to have employment before migrating to the United States.With the goal of opening up more jobs for U.S. citizens, Secretary of Labor William N. Doak began a campaign to prosecute illegal immigrants in the United States.Though Doak did not seek to deport one specific group of immigrants, his campaign most strongly affected Mexican Americans, especially Mexican Americans living in Southern California.