Illegal immigration in the presence of labor unions

"This paper develops a general equilibrium framework of a two-sector economy which incorporates illegal immigration in the presence of labor unions. It demonstrates that stricter enforcement of immigration laws, by reducing the demand for or supply of illegal aliens, benefits all legal workers in the economy. The model is used to evaluate the impact of these policy changes on national income. Results indicate that national income does not necessarily fall when immigration controls are tightened. The existence of a union mitigates the negative welfare impact of a reduction in the number of illegal immigrants."