The document discusses legal and illegal migration. It defines legal migration as migration with formal permission, while illegal migration is defined as entering a country without formal permission, such as illegal aliens or boat people. Some reasons for illegal migration include overpopulation, poverty, trade liberalization, and economics/labor market factors. Effects of illegal migration include rising unemployment, tax reductions, increased crime rates, and threats to traditional culture from different cultures. Proposed solutions include policy changes and repatriation programs.