This paper studies why illegal immigration is widespread. We develop a political agency model in which a politician decides on an immigration target and its enforcement, facing uncertainty on the supply of migrants. Illegal immigration can arise for two reasons: the policy maker may be unable to...

We develop a general model of legal and illegal immigration to understand the basic tradeoffs faced by a government in the decision to implement an immigration amnesty in the presence of a selective immigration policy. We show that two channels play an important role: an amnesty is more likely...