Illegals come here for two principal reasons: finding work, and looting social services. Lesser reasons are running the drug trade and to join predatory gangs. Taking care of the first two, the vast majority of the problem, is easy. 1. Employment. The law needs to change so that all employers have an AFFIRMATIVE DUTY to not hire anyone who is illegal. In support of that, the federal government needs to keep a database of all legal workers and all illegals who have attempted to work and been caught. This database will contain biometric data easily accesible on the net. If new employees are not already in the DB, they have to prove to employers (with such as birth certificates and affidavits) that they are legal. Employers will suffer severe penalties for deliberately evading the law or neglicence, not for honest mistakes. I suggest six months in jail and 1% of last years profits for a first offense, steeply accelerating for subsequent offenses. 2. Social services, especially medical. The same ID check is to be made for all non-emergency medical services - illegals are NOT eligible for such services, and those who provide them will be eligible for fines and jail terms. There you have it - the country would be cleared of 90% of illegals in a year. You wouldn't even NEED a wall - people cross the wall not because they like to tour the 110 degree desert, but for the looting opportunities.